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 A131681 #2 Oct 09 2013 02:24:34 %S A131681 0,1,8,48,384,1440,8640,40320,184320,829440,5529600,18247680,87588864, %T A131681 474439680,1532805120,7664025600,32699842560,130288435200, %U A131681 517321728000,2184247296000,9196830720000,38626689024000,188841590784000 %N A131681 Phi(binomial(2*n,n)*n^2) (phi of A002736 = Apery numbers: n^2 C(2n,n). ). %p A131681 with(numtheory):with(combinat):a:=n->phi(binomial(2*n,n)*n^2): seq(a(n), n=0..25); %Y A131681 Cf. A002736. %K A131681 nonn %O A131681 0,3 %A A131681 _Zerinvary Lajos_, Oct 07 2007