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 A211250 #7 Apr 07 2012 17:12:47 %S A211250 1,5,198,20548,4088918,1341552690,661685880676,460785157967228, %T A211250 432879460822014552,529918744425680488240,822575286838815581568992, %U A211250 1583737023708711008926884072,3713773722396456674797120593784,10445266376618187161982580673417192 %N A211250 E.g.f.: exp(-1)*Sum_{n>=0} (1+x)^(n^3)/n!. %F A211250 a(n) = Sum_{k=0..n} Stirling1(n, k)*Bell(3*k). %F A211250 a(n) = n!*exp(-1)*Sum_{k>=[n^(1/3)]} binomial(k^3,n)/k!. %e A211250 E.g.f.: A(x) = 1 + 5*x + 198*x^2/2! + 20548*x^3/3! + 4088918*x^4/4! +... %e A211250 such that %e A211250 A(x) = exp(-1)*(1 + (1+x) + (1+x)^8/2! + (1+x)^27/3! + (1+x)^64/4! +...). %o A211250 (PARI) {Stirling1(n, k)=n!*polcoeff(binomial(x, n), k)} %o A211250 {Bell(n)=n!*polcoeff(exp(exp(x+x*O(x^n))-1), n)} %o A211250 {a(n)=sum(k=0, n, Stirling1(n, k)*Bell(3*k))} %o A211250 for(n=0,15,print1(a(n),", ")) %Y A211250 Cf. A000110 (Bell), A014507, A211251, A211252. %K A211250 nonn %O A211250 0,2 %A A211250 _Paul D. Hanna_, Apr 07 2012