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 A385946 #8 Jul 13 2025 11:01:14
%S A385946 1,1,6,106,4176,316696,42104392,9172761368,3106804304704,
%T A385946 1567537597699840,1137145604406018176,1151190083860345401984,
%U A385946 1585522852991230263395584,2906652632758146061798315776,6959140466024956612239458880000,21400639132670591710876896798678016
%N A385946 a(0) = 1; a(n) = Sum_{k=0..n-1} binomial(k+4,4) * binomial(n-1,k) * a(k) * a(n-1-k).
%F A385946 E.g.f. A(x) satisfies A(x) = exp( Sum_{k=0..3} binomial(3,k) * x^(k+1)/(k+1)! * (d^k/dx^k A(x)) ), where (d^0/dx^0 A(x)) = A(x) by convention.
%o A385946 (PARI) a_vector(n) = my(v=vector(n+1)); v[1]=1; for(i=1, n, v[i+1]=sum(j=0, i-1, binomial(j+4, 4)*binomial(i-1, j)*v[j+1]*v[i-j])); v;
%Y A385946 Cf. A000272, A156325, A385945, A385947, A385948.
%Y A385946 Cf. A385953.
%K A385946 nonn
%O A385946 0,3
%A A385946 _Seiichi Manyama_, Jul 13 2025