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 A158615 #9 Dec 19 2015 06:43:50
%S A158615 1,5,19,105,601,4445,35281,324897,3266569,36360065,439084801,
%T A158615 5751188913,80951270401,1220673888257,19615124183329,334777645154817,
%U A158615 6046686277632001,115243914079782593,2311256907767808001
%N A158615 Expansion of Sum_{n>0} n*n!*x^n/(1-n!*x^n).
%C A158615 a(n) = Sum_{d|n} d*d!^(n/d).
%H A158615 Vaclav Kotesovec, <a href="/A158615/b158615.txt">Table of n, a(n) for n = 1..440</a>
%F A158615 a(n) ~ n * n!. - _Vaclav Kotesovec_, Dec 19 2015
%p A158615 nmax := 40: gf := add( taylor( n*n!*x^n/(1-n!*x^n),x=0,nmax+1),n=1..nmax ) : coeffs(convert(gf,polynom)) ; # _R. J. Mathar_, Mar 30 2009
%t A158615 nmax=20; Rest[CoefficientList[Series[Sum[k*k!*x^k/(1-k!*x^k), {k, 1, nmax}], {x, 0, nmax}], x]] (* _Vaclav Kotesovec_, Dec 19 2015 *)
%Y A158615 Cf. A077365, A265950.
%K A158615 easy,nonn
%O A158615 1,2
%A A158615 _Vladeta Jovovic_, Mar 22 2009
%E A158615 More terms from _R. J. Mathar_, Mar 30 2009