login

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).

A172155 as a simple table

na(n)
11
21
31
42
51
62
71
82
92
101
112
121
132
142
152
162
171
181
192
204
213
222
231
244
251
262
272
282
293
301
314
321
331
344
352
364
372
381
392
401
416
422
432
442
451
463
471
484
492
504
512
521
532
546
552
562
576
581
592
602
612
622
632
643
652
662
672
682
694
701
716
721
732
742
752
763
771
782
796
802
812
822
832
842
852
864
871
884
894
903
912
924
932
942
951
963
974
982
993
1001
1013
1022
1031
1048
1052

[1,1,1,2,1,2,1,2,2,1,2,1,2,2,2,2,1,1,2,4,3,2,1,4,
 1,2,2,2,3,1,4,1,1,4,2,4,2,1,2,1,6,2,2,2,1,3,1,4,2,
 4,2,1,2,6,2,2,6,1,2,2,2,2,2,3,2,2,2,2,4,1,6,1,2,2,
 2,3,1,2,6,2,2,2,2,2,2,4,1,4,4,3,2,4,2,2,1,3,4,2,3,
 1,3,2,1,8,2]