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 A227468 #9 Oct 08 2018 17:53:33 %S A227468 1,1,2,37,1562313,122131737394518,26010968765974205465787541, %T A227468 22347536974721066092798325076069521074882, %U A227468 113454243067016764816945424312979214671918840299656114590507,897202601035299299315214220213621062686601174611936477408260666612934393100592315294994 %N A227468 G.f.: exp( Sum_{n>=1} x^n/n * Sum_{k=0..n} binomial(n^3, n^2*k) * x^k ). %C A227468 Compare the definition to: exp( Sum_{n>=1} (1+y)^(n^3) * x^n/n ), which yields an integer series whenever y is an integer (e.g., A158110). %C A227468 Note: exp( Sum_{n>=1} (1+x)^(n^3) * x^n/n ) does not yield an integer series. %e A227468 G.f.: A(x) = 1 + x + 2*x^2 + 37*x^3 + 1562313*x^4 + 122131737394518*x^5 + ... %e A227468 such that the logarithm equals %e A227468 log(A(x)) = (1+x)*x + (1 + 70*x + x^2)*x^2/2 %e A227468 + (1 + 4686825*x + 4686825*x^2 + x^3)*x^3/3 %e A227468 + (1 + 488526937079580*x + 1832624140942590534*x^2 + 488526937079580*x^3 + x^4)*x^/4 + ... %o A227468 (PARI) {a(n)=polcoeff(exp(sum(m=1, n, sum(k=0, m, binomial(m^3, m^2*k)*x^k)*x^m/m)+x*O(x^n)), n)} %o A227468 for(n=0, 15, print1(a(n), ", ")) %Y A227468 Cf. A158110, A206830, A227467. %K A227468 nonn %O A227468 0,3 %A A227468 _Paul D. Hanna_, Aug 24 2013