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 A386507 #10 Jul 24 2025 07:23:26
%S A386507 1,1,3,151,49525,63641021,239036610181,2170214958201445,
%T A386507 41702857906969051017,1537709560908537888618409,
%U A386507 100904503302575334820438217641,11100605398391683050596962755215561,1950420777626865443224119613333235611309,525796384523344023260217345195483215249534941
%N A386507 a(0) = 1; a(n) = a(n-1) + Sum_{k=0..n-1} (1 + k) * k^4 * binomial(n-1,k) * a(k) * a(n-1-k).
%F A386507 E.g.f. A(x) satisfies A(x) = exp( x + x*Sum_{k=1..4} Stirling2(4,k) * x^k * (d^k/dx^k A(x)) ).
%o A386507 (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, (1+j)*j^4*binomial(i-1, j)*v[j+1]*v[i-j])); v;
%Y A386507 Cf. A143925, A386505, A386506, A386508, A386509.
%Y A386507 Cf. A385941, A386445.
%K A386507 nonn
%O A386507 0,3
%A A386507 _Seiichi Manyama_, Jul 24 2025