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 A386212 #11 Jul 16 2025 10:04:11
%S A386212 1,3,9,37,207,1455,12073,113949,1196499,13778155,172269777,2321464773,
%T A386212 33524717911,516428180631,8453096463321,146532991389613,
%U A386212 2682216423470763,51706945300407315,1047284621276095729,22237895367773398821,494041637873385734127,11462206075715032723903
%N A386212 G.f. A(x) satisfies A(x) = 1/(1-x)^3 + x^2*A(x)*A'(x).
%F A386212 a(n) = binomial(n+2,2) + (n-1)/2 * Sum_{k=0..n-1} a(k) * a(n-1-k).
%F A386212 a(n) = binomial(n+2,2) + Sum_{k=0..n-1} k * a(k) * a(n-1-k).
%o A386212 (PARI) a_vector(n) = my(v=vector(n+1)); for(i=0, n, v[i+1]=binomial(i+2, 2)+(i-1)/2*sum(j=0, i-1, v[j+1]*v[i-j])); v;
%Y A386212 Cf. A143917, A386211.
%Y A386212 Cf. A386210.
%K A386212 nonn
%O A386212 0,2
%A A386212 _Seiichi Manyama_, Jul 15 2025