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 A386448 #9 Jul 22 2025 09:52:04
%S A386448 1,1,1,3,23,319,6999,223725,9838405,570440733,42203958765,
%T A386448 3882243620535,434771830226307,58255737747374083,9203989127308306571,
%U A386448 1693477639607917108953,359008305377998952818761,86878355403079952880852217,23804317478591173659253678809,7331644401028481860472940727371
%N A386448 G.f. A(x) satisfies A(x) = 1/(1 - x - x^3*A''(x)).
%F A386448 a(0) = 1; a(n) = a(n-1) + Sum_{k=0..n-1} (-k + k^2) * a(k) * a(n-1-k).
%o A386448 (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, 2, stirling(2, k, 1)*j^k)*v[j+1]*v[i-j])); v;
%Y A386448 Cf. A075834, A386449, A386450, A386451.
%Y A386448 Cf. A385762.
%K A386448 nonn
%O A386448 0,4
%A A386448 _Seiichi Manyama_, Jul 22 2025