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 A206846 #13 Mar 30 2012 18:37:35
%S A206846 1,2,11,776,921193,10359730908,1620677532919905,
%T A206846 1969126979596399128130,32593711828578589304123599877,
%U A206846 3931730912701446701027876250509820962,6413805618092047206104426809813307222469463650,74040826359052943559114050244071546075856822107307951070
%N A206846 G.f.: exp( Sum_{n>=1} x^n/n * Sum_{k=0..n} binomial(n^2,k^2) * binomial(n^2,(n-k)^2) ).
%C A206846 Logarithmic derivative yields A206847.
%e A206846 G.f.: A(x) = 1 + 2*x + 11*x^2 + 776*x^3 + 921193*x^4 + 10359730908*x^5 +...
%e A206846 where the logarithm of the g.f. yields the l.g.f. of A206847:
%e A206846 log(A(x)) = 2*x + 18*x^2/2 + 2270*x^3/3 + 3678482*x^4/4 + 51789416252*x^5/5 +...
%o A206846 (PARI) {a(n)=polcoeff(exp(sum(m=1, n, sum(k=0, m, binomial(m^2,k^2)*binomial(m^2,(m-k)^2))*x^m/m)+x*O(x^n)), n)}
%o A206846 for(n=0, 25, print1(a(n), ", "))
%Y A206846 Cf. A206847 (log), A206848, A206850.
%K A206846 nonn
%O A206846 0,2
%A A206846 _Paul D. Hanna_, Feb 15 2012