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 A385948 #8 Jul 13 2025 11:01:05
%S A385948 1,1,8,246,21750,4689546,2197062708,2046202234224,3528088593902364,
%T A385948 10627093734265740672,53295889303479275834616,
%U A385948 427383379745842299684115608,5294446934064450139154214169992,98355143996083993836475641916586304,2669951662594756888115675117287929721248
%N A385948 a(0) = 1; a(n) = Sum_{k=0..n-1} binomial(k+6,6) * binomial(n-1,k) * a(k) * a(n-1-k).
%F A385948 E.g.f. A(x) satisfies A(x) = exp( Sum_{k=0..5} binomial(5,k) * x^(k+1)/(k+1)! * (d^k/dx^k A(x)) ), where (d^0/dx^0 A(x)) = A(x) by convention.
%o A385948 (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+6, 6)*binomial(i-1, j)*v[j+1]*v[i-j])); v;
%Y A385948 Cf. A000272, A156325, A385945, A385946, A385947.
%Y A385948 Cf. A385955.
%K A385948 nonn
%O A385948 0,3
%A A385948 _Seiichi Manyama_, Jul 13 2025