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 A195242 #23 Nov 29 2022 12:27:00 %S A195242 1,1,5,44,548,8808,173352,4036288,108507968,3307368320,112703108480, %T A195242 4245680193024,175200825481728,7859411394860032,380810598813553664, %U A195242 19819617775693512704,1102737068471914938368,65316500202537025634304,4103422475123595857854464 %N A195242 Expansion of Sum_{n>=0} n^n*x^n/(1 - n*x)^n. %C A195242 Compare g.f. to the identity (cf. A001710): %C A195242 Sum_{n>=0} n^n*x^n/(1 + n*x)^n = 1 + (1/2)*Sum_{n>=1} (n+1)!*x^n. %H A195242 Seiichi Manyama, <a href="/A195242/b195242.txt">Table of n, a(n) for n = 0..371</a> %F A195242 a(n) = Sum_{k=0..n} C(n-1,k)*(k+1)^n. %F A195242 a(n) = (n+1)!/2 + 2*Sum_{k=0..[n/2]} C(n-1,n-2*k)*(n-2*k+1)^n for n>0 with a(0)=1. %F A195242 a(n) ~ n^n * r^(n+3/2) / (exp(n) * (1-r)^n), where r = 1/(1+LambertW(exp(-1))) = 0.78218829428019990122... . - _Vaclav Kotesovec_, May 14 2014 %F A195242 a(n) = Sum_{k=0..n} (-1)^(n-k)*binomial(-k,-n)*k^n. Cf. A053506. - _Peter Luschny_, Apr 11 2016 %e A195242 G.f.: A(x) = 1 + x + 5*x^2 + 44*x^3 + 548*x^4 + 8808*x^5 + 173352*x^6 +... %e A195242 where %e A195242 A(x) = 1 + x/(1-x) + 2^2*x^2/(1-2*x)^2 + 3^3*x^3/(1-3*x)^3 + 4^4*x^4/(1-4*x)^4 +... %t A195242 a[n_] := Sum[Binomial[n - 1, k] (k + 1)^n, {k, 0, n}]; %t A195242 Table[a[n], {n, 0, 18}] (* _Jean-François Alcover_, Jun 26 2019 *) %o A195242 (PARI) {a(n)=polcoeff(sum(m=0,n,m^m*x^m/(1-m*x+x*O(x^n))^m),n)} %o A195242 (PARI) {a(n)=sum(k=0,n,binomial(n-1,k)*(k+1)^n)} %o A195242 (PARI) {a(n)=(n+1)!/2 + 2*sum(k=0,n\2,binomial(n-1,n-2*k)*(n-2*k+1)^n)} %Y A195242 Cf. A001710, A053506, A242449. %K A195242 nonn %O A195242 0,3 %A A195242 _Paul D. Hanna_, Sep 13 2011