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 A216373 #7 Nov 02 2014 12:36:52
%S A216373 1,1,3,12,65,419,3088,25557,233687,2331092,25130877,290632455,
%T A216373 3583432896,46864388137,647273948043,9406216355420,143356121222905,
%U A216373 2284850518224363,37988158312023376,657378186247162493,11816449728615690079,220230214060016856164
%N A216373 G.f.: Sum_{n>=0} x^n / Product_{k=0..n} (1 - (2*k-1)*x)^2.
%C A216373 Compare to o.g.f. of Dowling numbers: Sum_{n>=0} x^n / Product_{k=0..n} (1 - (2*k-1)*x).
%H A216373 Vaclav Kotesovec, <a href="/A216373/b216373.txt">Table of n, a(n) for n = 0..300</a>
%e A216373 G.f.: A(x) = 1 + x + 3*x^2 + 12*x^3 + 65*x^4 + 419*x^5 + 3088*x^6 +...
%e A216373 where
%e A216373 A(x) = 1 + x/(1-x)^2 + x^2/((1-x)*(1-3*x))^2 + x^3/((1-x)*(1-3*x)*(1-5*x))^2 + x^4/((1-x)*(1-3*x)*(1-5*x)*(1-7*x))^2 +...
%o A216373 (PARI) {a(n)=polcoeff(sum(m=0, n, x^m/prod(k=1, m, 1-(2*k-1)*x +x*O(x^n))^2), n)}
%o A216373 for(n=0,30,print1(a(n),", "))
%Y A216373 Cf. A216367, A007405.
%K A216373 nonn
%O A216373 0,3
%A A216373 _Paul D. Hanna_, Sep 05 2012