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”).

A104731 as a triangular array

1
12
153
15114
1516195
151637296
15164471417
151644103121558
151644112211190719
1516441122613902818910
15164411227255566639710911

A104731 as a square array

11111111111
2555555555
31116161616161616
419374444444444
52971103112112112
641121211261272
755190390555
871281666
989397
10109
11
11111111111
2555555555
31116161616161616
419374444444444
52971103112112112
641121211261272
755190390555
871281666
989397
10109
11