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 A009448 #27 Oct 02 2021 07:57:18
%S A009448 0,1,2,2,-8,-84,-504,-2304,-6656,15760,484000,5348320,44393856,
%T A009448 288642368,1137006976,-5372233216,-195241910272,-2961479980800,
%U A009448 -34259767672320,-320473550808576,-2158264400250880,-1727938748171264,278774033845987328
%N A009448 E.g.f. sin(x*exp(x)).
%H A009448 Seiichi Manyama, <a href="/A009448/b009448.txt">Table of n, a(n) for n = 0..100</a>
%F A009448 a(n) = Sum_{j=0..(n-1)/2} binomial(n,2*j+1)*(2*j+1)^(n-2*j-1)*(-1)^j. - _Vladimir Kruchinin_, Jun 10 2011
%t A009448 With[{nn=30},CoefficientList[Series[Sin[x Exp[x]],{x,0,nn}],x] Range[0,nn]!] (* _Harvey P. Dale_, Mar 17 2012 *)
%o A009448 (Maxima)
%o A009448 a(n):=sum(binomial(n,2*j+1)*(2*j+1)^(n-2*j-1)*(-1)^j,j,0,(n-1)/2); /* _Vladimir Kruchinin_, Jun 10 2011 */
%Y A009448 Cf. A009017, A009565, A009635, A297009.
%K A009448 sign,easy
%O A009448 0,3
%A A009448 _R. H. Hardin_
%E A009448 Extended with signs by _Olivier Gérard_, Mar 15 1997