List of Partial Sums of Natural Numbers up to 1,000

For your convenience, I created a list of partial sums of natural numbers from 1 to 1,000. So, S(1) = first partial sum, S(2) = second partial sum, S(3) = third partial sum, S(4) = fourth partial sum, and so on.

You can use this list as an answer key to practice finding the sum of the first \large\color{red}n natural numbers using the arithmetic series formula.


S (1) = 1
S (2) = 3
S (3) = 6
S (4) = 10
S (5) = 15
S (6) = 21
S (7) = 28
S (8) = 36
S (9) = 45
S (10) = 55
S (11) = 66
S (12) = 78
S (13) = 91
S (14) = 105
S (15) = 120
S (16) = 136
S (17) = 153
S (18) = 171
S (19) = 190
S (20) = 210
S (21) = 231
S (22) = 253
S (23) = 276
S (24) = 300
S (25) = 325
S (26) = 351
S (27) = 378
S (28) = 406
S (29) = 435
S (30) = 465
S (31) = 496
S (32) = 528
S (33) = 561
S (34) = 595
S (35) = 630
S (36) = 666
S (37) = 703
S (38) = 741
S (39) = 780
S (40) = 820
S (41) = 861
S (42) = 903
S (43) = 946
S (44) = 990
S (45) = 1035
S (46) = 1081
S (47) = 1128
S (48) = 1176
S (49) = 1225
S (50) = 1275
S (51) = 1326
S (52) = 1378
S (53) = 1431
S (54) = 1485
S (55) = 1540
S (56) = 1596
S (57) = 1653
S (58) = 1711
S (59) = 1770
S (60) = 1830
S (61) = 1891
S (62) = 1953
S (63) = 2016
S (64) = 2080
S (65) = 2145
S (66) = 2211
S (67) = 2278
S (68) = 2346
S (69) = 2415
S (70) = 2485
S (71) = 2556
S (72) = 2628
S (73) = 2701
S (74) = 2775
S (75) = 2850
S (76) = 2926
S (77) = 3003
S (78) = 3081
S (79) = 3160
S (80) = 3240
S (81) = 3321
S (82) = 3403
S (83) = 3486
S (84) = 3570
S (85) = 3655
S (86) = 3741
S (87) = 3828
S (88) = 3916
S (89) = 4005
S (90) = 4095
S (91) = 4186
S (92) = 4278
S (93) = 4371
S (94) = 4465
S (95) = 4560
S (96) = 4656
S (97) = 4753
S (98) = 4851
S (99) = 4950
S (100) = 5050
S (101) = 5151
S (102) = 5253
S (103) = 5356
S (104) = 5460
S (105) = 5565
S (106) = 5671
S (107) = 5778
S (108) = 5886
S (109) = 5995
S (110) = 6105
S (111) = 6216
S (112) = 6328
S (113) = 6441
S (114) = 6555
S (115) = 6670
S (116) = 6786
S (117) = 6903
S (118) = 7021
S (119) = 7140
S (120) = 7260
S (121) = 7381
S (122) = 7503
S (123) = 7626
S (124) = 7750
S (125) = 7875
S (126) = 8001
S (127) = 8128
S (128) = 8256
S (129) = 8385
S (130) = 8515
S (131) = 8646
S (132) = 8778
S (133) = 8911
S (134) = 9045
S (135) = 9180
S (136) = 9316
S (137) = 9453
S (138) = 9591
S (139) = 9730
S (140) = 9870
S (141) = 10011
S (142) = 10153
S (143) = 10296
S (144) = 10440
S (145) = 10585
S (146) = 10731
S (147) = 10878
S (148) = 11026
S (149) = 11175
S (150) = 11325
S (151) = 11476
S (152) = 11628
S (153) = 11781
S (154) = 11935
S (155) = 12090
S (156) = 12246
S (157) = 12403
S (158) = 12561
S (159) = 12720
S (160) = 12880
S (161) = 13041
S (162) = 13203
S (163) = 13366
S (164) = 13530
S (165) = 13695
S (166) = 13861
S (167) = 14028
S (168) = 14196
S (169) = 14365
S (170) = 14535
S (171) = 14706
S (172) = 14878
S (173) = 15051
S (174) = 15225
S (175) = 15400
S (176) = 15576
S (177) = 15753
S (178) = 15931
S (179) = 16110
S (180) = 16290
S (181) = 16471
S (182) = 16653
S (183) = 16836
S (184) = 17020
S (185) = 17205
S (186) = 17391
S (187) = 17578
S (188) = 17766
S (189) = 17955
S (190) = 18145
S (191) = 18336
S (192) = 18528
S (193) = 18721
S (194) = 18915
S (195) = 19110
S (196) = 19306
S (197) = 19503
S (198) = 19701
S (199) = 19900
S (200) = 20100
S (201) = 20301
S (202) = 20503
S (203) = 20706
S (204) = 20910
S (205) = 21115
S (206) = 21321
S (207) = 21528
S (208) = 21736
S (209) = 21945
S (210) = 22155
S (211) = 22366
S (212) = 22578
S (213) = 22791
S (214) = 23005
S (215) = 23220
S (216) = 23436
S (217) = 23653
S (218) = 23871
S (219) = 24090
S (220) = 24310
S (221) = 24531
S (222) = 24753
S (223) = 24976
S (224) = 25200
S (225) = 25425
S (226) = 25651
S (227) = 25878
S (228) = 26106
S (229) = 26335
S (230) = 26565
S (231) = 26796
S (232) = 27028
S (233) = 27261
S (234) = 27495
S (235) = 27730
S (236) = 27966
S (237) = 28203
S (238) = 28441
S (239) = 28680
S (240) = 28920
S (241) = 29161
S (242) = 29403
S (243) = 29646
S (244) = 29890
S (245) = 30135
S (246) = 30381
S (247) = 30628
S (248) = 30876
S (249) = 31125
S (250) = 31375
S (251) = 31626
S (252) = 31878
S (253) = 32131
S (254) = 32385
S (255) = 32640
S (256) = 32896
S (257) = 33153
S (258) = 33411
S (259) = 33670
S (260) = 33930
S (261) = 34191
S (262) = 34453
S (263) = 34716
S (264) = 34980
S (265) = 35245
S (266) = 35511
S (267) = 35778
S (268) = 36046
S (269) = 36315
S (270) = 36585
S (271) = 36856
S (272) = 37128
S (273) = 37401
S (274) = 37675
S (275) = 37950
S (276) = 38226
S (277) = 38503
S (278) = 38781
S (279) = 39060
S (280) = 39340
S (281) = 39621
S (282) = 39903
S (283) = 40186
S (284) = 40470
S (285) = 40755
S (286) = 41041
S (287) = 41328
S (288) = 41616
S (289) = 41905
S (290) = 42195
S (291) = 42486
S (292) = 42778
S (293) = 43071
S (294) = 43365
S (295) = 43660
S (296) = 43956
S (297) = 44253
S (298) = 44551
S (299) = 44850
S (300) = 45150
S (301) = 45451
S (302) = 45753
S (303) = 46056
S (304) = 46360
S (305) = 46665
S (306) = 46971
S (307) = 47278
S (308) = 47586
S (309) = 47895
S (310) = 48205
S (311) = 48516
S (312) = 48828
S (313) = 49141
S (314) = 49455
S (315) = 49770
S (316) = 50086
S (317) = 50403
S (318) = 50721
S (319) = 51040
S (320) = 51360
S (321) = 51681
S (322) = 52003
S (323) = 52326
S (324) = 52650
S (325) = 52975
S (326) = 53301
S (327) = 53628
S (328) = 53956
S (329) = 54285
S (330) = 54615
S (331) = 54946
S (332) = 55278
S (333) = 55611
S (334) = 55945
S (335) = 56280
S (336) = 56616
S (337) = 56953
S (338) = 57291
S (339) = 57630
S (340) = 57970
S (341) = 58311
S (342) = 58653
S (343) = 58996
S (344) = 59340
S (345) = 59685
S (346) = 60031
S (347) = 60378
S (348) = 60726
S (349) = 61075
S (350) = 61425
S (351) = 61776
S (352) = 62128
S (353) = 62481
S (354) = 62835
S (355) = 63190
S (356) = 63546
S (357) = 63903
S (358) = 64261
S (359) = 64620
S (360) = 64980
S (361) = 65341
S (362) = 65703
S (363) = 66066
S (364) = 66430
S (365) = 66795
S (366) = 67161
S (367) = 67528
S (368) = 67896
S (369) = 68265
S (370) = 68635
S (371) = 69006
S (372) = 69378
S (373) = 69751
S (374) = 70125
S (375) = 70500
S (376) = 70876
S (377) = 71253
S (378) = 71631
S (379) = 72010
S (380) = 72390
S (381) = 72771
S (382) = 73153
S (383) = 73536
S (384) = 73920
S (385) = 74305
S (386) = 74691
S (387) = 75078
S (388) = 75466
S (389) = 75855
S (390) = 76245
S (391) = 76636
S (392) = 77028
S (393) = 77421
S (394) = 77815
S (395) = 78210
S (396) = 78606
S (397) = 79003
S (398) = 79401
S (399) = 79800
S (400) = 80200
S (401) = 80601
S (402) = 81003
S (403) = 81406
S (404) = 81810
S (405) = 82215
S (406) = 82621
S (407) = 83028
S (408) = 83436
S (409) = 83845
S (410) = 84255
S (411) = 84666
S (412) = 85078
S (413) = 85491
S (414) = 85905
S (415) = 86320
S (416) = 86736
S (417) = 87153
S (418) = 87571
S (419) = 87990
S (420) = 88410
S (421) = 88831
S (422) = 89253
S (423) = 89676
S (424) = 90100
S (425) = 90525
S (426) = 90951
S (427) = 91378
S (428) = 91806
S (429) = 92235
S (430) = 92665
S (431) = 93096
S (432) = 93528
S (433) = 93961
S (434) = 94395
S (435) = 94830
S (436) = 95266
S (437) = 95703
S (438) = 96141
S (439) = 96580
S (440) = 97020
S (441) = 97461
S (442) = 97903
S (443) = 98346
S (444) = 98790
S (445) = 99235
S (446) = 99681
S (447) = 100128
S (448) = 100576
S (449) = 101025
S (450) = 101475
S (451) = 101926
S (452) = 102378
S (453) = 102831
S (454) = 103285
S (455) = 103740
S (456) = 104196
S (457) = 104653
S (458) = 105111
S (459) = 105570
S (460) = 106030
S (461) = 106491
S (462) = 106953
S (463) = 107416
S (464) = 107880
S (465) = 108345
S (466) = 108811
S (467) = 109278
S (468) = 109746
S (469) = 110215
S (470) = 110685
S (471) = 111156
S (472) = 111628
S (473) = 112101
S (474) = 112575
S (475) = 113050
S (476) = 113526
S (477) = 114003
S (478) = 114481
S (479) = 114960
S (480) = 115440
S (481) = 115921
S (482) = 116403
S (483) = 116886
S (484) = 117370
S (485) = 117855
S (486) = 118341
S (487) = 118828
S (488) = 119316
S (489) = 119805
S (490) = 120295
S (491) = 120786
S (492) = 121278
S (493) = 121771
S (494) = 122265
S (495) = 122760
S (496) = 123256
S (497) = 123753
S (498) = 124251
S (499) = 124750
S (500) = 125250
S (501) = 125751
S (502) = 126253
S (503) = 126756
S (504) = 127260
S (505) = 127765
S (506) = 128271
S (507) = 128778
S (508) = 129286
S (509) = 129795
S (510) = 130305
S (511) = 130816
S (512) = 131328
S (513) = 131841
S (514) = 132355
S (515) = 132870
S (516) = 133386
S (517) = 133903
S (518) = 134421
S (519) = 134940
S (520) = 135460
S (521) = 135981
S (522) = 136503
S (523) = 137026
S (524) = 137550
S (525) = 138075
S (526) = 138601
S (527) = 139128
S (528) = 139656
S (529) = 140185
S (530) = 140715
S (531) = 141246
S (532) = 141778
S (533) = 142311
S (534) = 142845
S (535) = 143380
S (536) = 143916
S (537) = 144453
S (538) = 144991
S (539) = 145530
S (540) = 146070
S (541) = 146611
S (542) = 147153
S (543) = 147696
S (544) = 148240
S (545) = 148785
S (546) = 149331
S (547) = 149878
S (548) = 150426
S (549) = 150975
S (550) = 151525
S (551) = 152076
S (552) = 152628
S (553) = 153181
S (554) = 153735
S (555) = 154290
S (556) = 154846
S (557) = 155403
S (558) = 155961
S (559) = 156520
S (560) = 157080
S (561) = 157641
S (562) = 158203
S (563) = 158766
S (564) = 159330
S (565) = 159895
S (566) = 160461
S (567) = 161028
S (568) = 161596
S (569) = 162165
S (570) = 162735
S (571) = 163306
S (572) = 163878
S (573) = 164451
S (574) = 165025
S (575) = 165600
S (576) = 166176
S (577) = 166753
S (578) = 167331
S (579) = 167910
S (580) = 168490
S (581) = 169071
S (582) = 169653
S (583) = 170236
S (584) = 170820
S (585) = 171405
S (586) = 171991
S (587) = 172578
S (588) = 173166
S (589) = 173755
S (590) = 174345
S (591) = 174936
S (592) = 175528
S (593) = 176121
S (594) = 176715
S (595) = 177310
S (596) = 177906
S (597) = 178503
S (598) = 179101
S (599) = 179700
S (600) = 180300
S (601) = 180901
S (602) = 181503
S (603) = 182106
S (604) = 182710
S (605) = 183315
S (606) = 183921
S (607) = 184528
S (608) = 185136
S (609) = 185745
S (610) = 186355
S (611) = 186966
S (612) = 187578
S (613) = 188191
S (614) = 188805
S (615) = 189420
S (616) = 190036
S (617) = 190653
S (618) = 191271
S (619) = 191890
S (620) = 192510
S (621) = 193131
S (622) = 193753
S (623) = 194376
S (624) = 195000
S (625) = 195625
S (626) = 196251
S (627) = 196878
S (628) = 197506
S (629) = 198135
S (630) = 198765
S (631) = 199396
S (632) = 200028
S (633) = 200661
S (634) = 201295
S (635) = 201930
S (636) = 202566
S (637) = 203203
S (638) = 203841
S (639) = 204480
S (640) = 205120
S (641) = 205761
S (642) = 206403
S (643) = 207046
S (644) = 207690
S (645) = 208335
S (646) = 208981
S (647) = 209628
S (648) = 210276
S (649) = 210925
S (650) = 211575
S (651) = 212226
S (652) = 212878
S (653) = 213531
S (654) = 214185
S (655) = 214840
S (656) = 215496
S (657) = 216153
S (658) = 216811
S (659) = 217470
S (660) = 218130
S (661) = 218791
S (662) = 219453
S (663) = 220116
S (664) = 220780
S (665) = 221445
S (666) = 222111
S (667) = 222778
S (668) = 223446
S (669) = 224115
S (670) = 224785
S (671) = 225456
S (672) = 226128
S (673) = 226801
S (674) = 227475
S (675) = 228150
S (676) = 228826
S (677) = 229503
S (678) = 230181
S (679) = 230860
S (680) = 231540
S (681) = 232221
S (682) = 232903
S (683) = 233586
S (684) = 234270
S (685) = 234955
S (686) = 235641
S (687) = 236328
S (688) = 237016
S (689) = 237705
S (690) = 238395
S (691) = 239086
S (692) = 239778
S (693) = 240471
S (694) = 241165
S (695) = 241860
S (696) = 242556
S (697) = 243253
S (698) = 243951
S (699) = 244650
S (700) = 245350
S (701) = 246051
S (702) = 246753
S (703) = 247456
S (704) = 248160
S (705) = 248865
S (706) = 249571
S (707) = 250278
S (708) = 250986
S (709) = 251695
S (710) = 252405
S (711) = 253116
S (712) = 253828
S (713) = 254541
S (714) = 255255
S (715) = 255970
S (716) = 256686
S (717) = 257403
S (718) = 258121
S (719) = 258840
S (720) = 259560
S (721) = 260281
S (722) = 261003
S (723) = 261726
S (724) = 262450
S (725) = 263175
S (726) = 263901
S (727) = 264628
S (728) = 265356
S (729) = 266085
S (730) = 266815
S (731) = 267546
S (732) = 268278
S (733) = 269011
S (734) = 269745
S (735) = 270480
S (736) = 271216
S (737) = 271953
S (738) = 272691
S (739) = 273430
S (740) = 274170
S (741) = 274911
S (742) = 275653
S (743) = 276396
S (744) = 277140
S (745) = 277885
S (746) = 278631
S (747) = 279378
S (748) = 280126
S (749) = 280875
S (750) = 281625
S (751) = 282376
S (752) = 283128
S (753) = 283881
S (754) = 284635
S (755) = 285390
S (756) = 286146
S (757) = 286903
S (758) = 287661
S (759) = 288420
S (760) = 289180
S (761) = 289941
S (762) = 290703
S (763) = 291466
S (764) = 292230
S (765) = 292995
S (766) = 293761
S (767) = 294528
S (768) = 295296
S (769) = 296065
S (770) = 296835
S (771) = 297606
S (772) = 298378
S (773) = 299151
S (774) = 299925
S (775) = 300700
S (776) = 301476
S (777) = 302253
S (778) = 303031
S (779) = 303810
S (780) = 304590
S (781) = 305371
S (782) = 306153
S (783) = 306936
S (784) = 307720
S (785) = 308505
S (786) = 309291
S (787) = 310078
S (788) = 310866
S (789) = 311655
S (790) = 312445
S (791) = 313236
S (792) = 314028
S (793) = 314821
S (794) = 315615
S (795) = 316410
S (796) = 317206
S (797) = 318003
S (798) = 318801
S (799) = 319600
S (800) = 320400
S (801) = 321201
S (802) = 322003
S (803) = 322806
S (804) = 323610
S (805) = 324415
S (806) = 325221
S (807) = 326028
S (808) = 326836
S (809) = 327645
S (810) = 328455
S (811) = 329266
S (812) = 330078
S (813) = 330891
S (814) = 331705
S (815) = 332520
S (816) = 333336
S (817) = 334153
S (818) = 334971
S (819) = 335790
S (820) = 336610
S (821) = 337431
S (822) = 338253
S (823) = 339076
S (824) = 339900
S (825) = 340725
S (826) = 341551
S (827) = 342378
S (828) = 343206
S (829) = 344035
S (830) = 344865
S (831) = 345696
S (832) = 346528
S (833) = 347361
S (834) = 348195
S (835) = 349030
S (836) = 349866
S (837) = 350703
S (838) = 351541
S (839) = 352380
S (840) = 353220
S (841) = 354061
S (842) = 354903
S (843) = 355746
S (844) = 356590
S (845) = 357435
S (846) = 358281
S (847) = 359128
S (848) = 359976
S (849) = 360825
S (850) = 361675
S (851) = 362526
S (852) = 363378
S (853) = 364231
S (854) = 365085
S (855) = 365940
S (856) = 366796
S (857) = 367653
S (858) = 368511
S (859) = 369370
S (860) = 370230
S (861) = 371091
S (862) = 371953
S (863) = 372816
S (864) = 373680
S (865) = 374545
S (866) = 375411
S (867) = 376278
S (868) = 377146
S (869) = 378015
S (870) = 378885
S (871) = 379756
S (872) = 380628
S (873) = 381501
S (874) = 382375
S (875) = 383250
S (876) = 384126
S (877) = 385003
S (878) = 385881
S (879) = 386760
S (880) = 387640
S (881) = 388521
S (882) = 389403
S (883) = 390286
S (884) = 391170
S (885) = 392055
S (886) = 392941
S (887) = 393828
S (888) = 394716
S (889) = 395605
S (890) = 396495
S (891) = 397386
S (892) = 398278
S (893) = 399171
S (894) = 400065
S (895) = 400960
S (896) = 401856
S (897) = 402753
S (898) = 403651
S (899) = 404550
S (900) = 405450
S (901) = 406351
S (902) = 407253
S (903) = 408156
S (904) = 409060
S (905) = 409965
S (906) = 410871
S (907) = 411778
S (908) = 412686
S (909) = 413595
S (910) = 414505
S (911) = 415416
S (912) = 416328
S (913) = 417241
S (914) = 418155
S (915) = 419070
S (916) = 419986
S (917) = 420903
S (918) = 421821
S (919) = 422740
S (920) = 423660
S (921) = 424581
S (922) = 425503
S (923) = 426426
S (924) = 427350
S (925) = 428275
S (926) = 429201
S (927) = 430128
S (928) = 431056
S (929) = 431985
S (930) = 432915
S (931) = 433846
S (932) = 434778
S (933) = 435711
S (934) = 436645
S (935) = 437580
S (936) = 438516
S (937) = 439453
S (938) = 440391
S (939) = 441330
S (940) = 442270
S (941) = 443211
S (942) = 444153
S (943) = 445096
S (944) = 446040
S (945) = 446985
S (946) = 447931
S (947) = 448878
S (948) = 449826
S (949) = 450775
S (950) = 451725
S (951) = 452676
S (952) = 453628
S (953) = 454581
S (954) = 455535
S (955) = 456490
S (956) = 457446
S (957) = 458403
S (958) = 459361
S (959) = 460320
S (960) = 461280
S (961) = 462241
S (962) = 463203
S (963) = 464166
S (964) = 465130
S (965) = 466095
S (966) = 467061
S (967) = 468028
S (968) = 468996
S (969) = 469965
S (970) = 470935
S (971) = 471906
S (972) = 472878
S (973) = 473851
S (974) = 474825
S (975) = 475800
S (976) = 476776
S (977) = 477753
S (978) = 478731
S (979) = 479710
S (980) = 480690
S (981) = 481671
S (982) = 482653
S (983) = 483636
S (984) = 484620
S (985) = 485605
S (986) = 486591
S (987) = 487578
S (988) = 488566
S (989) = 489555
S (990) = 490545
S (991) = 491536
S (992) = 492528
S (993) = 493521
S (994) = 494515
S (995) = 495510
S (996) = 496506
S (997) = 497503
S (998) = 498501
S (999) = 499500
S (1000) = 500500