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 A226968 #14 Nov 03 2024 04:33:18
%S A226968 0,1,1,8,30,264,1920,20880,226800,3064320,43908480,722131200,
%T A226968 12773376000,249559833600,5236924492800,118911189196800,
%U A226968 2883421981440000,74715282690048000,2054450584682496000,59855791774851072000,1839882143683584000000
%N A226968 Number of labeled octopi with n nodes such that each tentacle has an odd number of nodes.
%F A226968 For n>=1; (n-1)!*( A000032(n) + (-1)^(n+1) -1 ).
%F A226968 E.g.f.: log(1/(1 - A(x))) where A(x) = x/(1-x^2).
%t A226968 nn=20;f[x_]:=x/(1-x^2);Range[0,nn]!CoefficientList[Series[Log[1/(1-f[x])],{x,0,nn}],x]
%Y A226968 Cf. A029767.
%K A226968 nonn
%O A226968 0,4
%A A226968 _Geoffrey Critzer_, Sep 01 2013