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 A059488 #3 Mar 30 2012 16:49:03
%S A059488 1,6,140,12936,4756752,6974908512,40825196325056,954410297723625600,
%T A059488 89149543741372647686400,33280303224443643993143232000,
%U A059488 49660896290963321355372907102080000,296248087478941460167300263349693113600000,7065635944743752671502919147104799866118720000000
%N A059488 Expansion of generating function A_{UU}^(2)(4n;2,1,1).
%H A059488 G. Kuperberg, <a href="http://arXiv.org/abs/math.CO/0008184">Symmetry classes of alternating-sign matrices under one roof, arXiv math.CO/0008184</a> [Th. 5]
%p A059488 A059488 := proc(n) local i, j, t1; t1 := 2^(n^2 + 2*n); for i to 2*n + 1 do for j to 2*n + 1 do if i mod 2 <> 0 and j mod 2 = 0 then t1 := t1*(2*j - 2*i + 1)/(2*j - 2*i) end if end do end do; t1 end proc;
%K A059488 nonn,easy
%O A059488 0,2
%A A059488 _N. J. A. Sloane_, Feb 04 2001