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 A368015 #8 Dec 08 2023 09:57:09
%S A368015 1,-1,-3,5,81,29,-4623,-20035,415041,4838909,-46093743,-1309934275,
%T A368015 3230184801,419574363389,2065056788337,-154120122603715,
%U A368015 -2307971235744639,59954627542249469,1959892188447337617,-19474957767402204355,-1658215397958862557279
%N A368015 Expansion of e.g.f. 1/(1 - exp(2*x) + exp(3*x)).
%F A368015 a(0) = 1; a(n) = Sum_{k=1..n} (2^k - 3^k) * binomial(n,k) * a(n-k).
%o A368015 (PARI) a_vector(n) = my(v=vector(n+1)); v[1]=1; for(i=1, n, v[i+1]=sum(j=1, i, (2^j-3^j)*binomial(i, j)*v[i-j+1])); v;
%Y A368015 Cf. A355409.
%K A368015 sign
%O A368015 0,3
%A A368015 _Seiichi Manyama_, Dec 08 2023