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 A137941 #2 Mar 30 2012 18:37:09
%S A137941 1,1,1,-3,6,10,-195,945,-3080,17136,37170,-796950,3880800,122007600,
%T A137941 -2380685307,18531377865,-136619683200,942469528000,723819456360,
%U A137941 -118481659031736,1884943573381440,-16067035945724400,-323306803861791750,15940746503392961250
%N A137941 G.f.: exp(x) = Product_{n>=1} [1 + a(2n-1)*x^(2n-1)/(2n-1)! + a(2n)*x^(2n)/(2n)! ].
%C A137941 a(n) appears to be divisible by (n-1)(n-2)/2 for n>2.
%e A137941 exp(x) = (1 + 1*x + 1*x^2/2!) * (1 + 1*x^3/3! - 3*x^4/4!) * (1 + 6*x^5/5! + 10*x^6/6!) * (1 - 195*x^7/7! + 945*x^8/8!) *...
%o A137941 (PARI) {a(n)=if(n<1, 0, n!*polcoeff(exp(x +x*O(x^n))/prod(k=1, (n-1)\2, 1+a(2*k-1)*x^(2*k-1)/(2*k-1)!+a(2*k)*x^(2*k)/(2*k)! +x*O(x^n)), n))}
%Y A137941 Cf. A137852.
%K A137941 sign
%O A137941 1,4
%A A137941 _Paul D. Hanna_, Feb 23 2008