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 A367877 #10 Apr 13 2025 11:42:59
%S A367877 1,1,-3,-17,-7,331,1669,-2561,-82447,-411821,1602941,38344615,
%T A367877 209694121,-1133998085,-29424823819,-194721585329,978185645537,
%U A367877 33795275629219,290738927334637,-827164853506313,-53319390538573159,-621202281347942069,-249829452752930203
%N A367877 Expansion of e.g.f. exp(x * (3 - 2*exp(x))).
%F A367877 G.f.: Sum_{k>=0} (-2*x)^k / (1 - (k+3)*x)^(k+1).
%F A367877 a(n) = Sum_{k=0..n} (-2)^k * (k+3)^(n-k) * binomial(n,k).
%t A367877 With[{nn=30},CoefficientList[Series[Exp[x(3-2Exp[x])],{x,0,nn}],x] Range[0,nn]!] (* _Harvey P. Dale_, Apr 13 2025 *)
%o A367877 (PARI) a(n) = sum(k=0, n, (-2)^k*(k+3)^(n-k)*binomial(n, k));
%Y A367877 Cf. A367876.
%K A367877 sign,easy
%O A367877 0,3
%A A367877 _Seiichi Manyama_, Dec 03 2023