This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A123256 #8 Sep 03 2015 10:29:42 %S A123256 1,2,3,6,10,24,49,121,289,730,1843,4794,12487 %N A123256 Dimension of the invariant subspace in modules over the symmetric groups S_n of dimension n*(n+1)^(n-1). %C A123256 No simple formula known, just a complicated sum over partitions. %C A123256 Empirically a(n+1) = sum( d divides n, A000081(d) ), this holds for the terms given. If true, this sequences starts 1, 2, 3, 6, 10, 24, 49, 121, 289, 730, 1843, 4794, 12487, 33023, 87823, 235502, 634848, 1721469, 4688677, 12826962, 35221883, 97057025, 268282856, 743729893, 2067174655, ... . - _Joerg Arndt_, Sep 03 2015 %e A123256 a(5)=6 from the module 2 s[1, 1, 1, 1, 1] + 9 s[2, 1, 1, 1] + 14 s[2, 2, 1] + 14 s[3, 1, 1] + 14 s[3,2] + 13 s[4, 1] + 6 s[5]. %Y A123256 Cf. A000081, A098091. %K A123256 nonn,more %O A123256 2,2 %A A123256 _F. Chapoton_, Oct 09 2006