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 A167029 #16 Feb 16 2015 04:10:45
%S A167029 1,0,2,0,8,0,18,0,578,0,-15460,0,1012512,0,-81237604,0,8572174172,0,
%T A167029 -1139408178984,0,186543348044576,0,-36888247922732008,0,
%U A167029 8669441321229610968,0,-2388740252077518073072,0,762715125987833507921408,0,-279382350611903941569174000,0
%N A167029 Difference between the number of positive and negative terms in the expansion of a skew symmetric matrix of order n.
%C A167029 For even n, a(n)=0.
%F A167029 E.g.f. (for offset 2): sqrt(cosh(x))*exp(x^2/4).
%F A167029 Asymptotics (for even n): a(n)=exp(Pi^2/16)*(2^(n-2))*(n!)*(Pi^(-n))*n^(3/4)*(1+O(1/n)) [This formula is wrong. - _Vaclav Kotesovec_, Feb 15 2015]
%F A167029 If n is odd |a(n)| ~ exp(-Pi^2/16) * 2^(n+1/2) * n! / (sqrt(n) * Pi^(n+1)). - _Vaclav Kotesovec_, Feb 15 2015
%t A167029 Rest[Rest[CoefficientList[Series[Sqrt[Cosh[x]]*E^(x^2/4), {x, 0, 20}], x] * Range[0, 20]!]] (* _Vaclav Kotesovec_, Feb 15 2015 *)
%Y A167029 Cf. A167028.
%K A167029 easy,nice,sign
%O A167029 1,3
%A A167029 _Pietro Majer_, Oct 27 2009
%E A167029 More terms from _Vaclav Kotesovec_, Feb 15 2015