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 A386449 #9 Jul 22 2025 09:51:48
%S A386449 1,1,1,1,7,181,11215,1368049,290015209,98023774645,49599740115757,
%T A386449 35810914359761065,35524377449180431975,46963191178201310535625,
%U A386449 80682726920407341929523811,176372394085267937467487988481,481849299958664384125278899595601,1619977170089211596368385150640702601
%N A386449 G.f. A(x) satisfies A(x) = 1/(1 - x - x^4*A'''(x)).
%F A386449 a(0) = 1; a(n) = a(n-1) + Sum_{k=0..n-1} (2*k - 3*k^2 + k^3) * a(k) * a(n-1-k).
%o A386449 (PARI) a_vector(n) = my(v=vector(n+1)); v[1]=1; for(i=1, n, v[i+1]=v[i]+sum(j=0, i-1, sum(k=1, 3, stirling(3, k, 1)*j^k)*v[j+1]*v[i-j])); v;
%Y A386449 Cf. A075834, A386448, A386450, A386451.
%Y A386449 Cf. A385763.
%K A386449 nonn
%O A386449 0,5
%A A386449 _Seiichi Manyama_, Jul 22 2025