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 A385875 #8 Jul 11 2025 08:49:26
%S A385875 1,1,2,10,111,2347,84757,4837213,411373408,49787445476,8265626303452,
%T A385875 1826809978098228,524311794034090050,191377585766768936606,
%U A385875 87269255118865044728501,48958442598180565027265909,33340876732769115354996751746,27239595466972699678481509900786
%N A385875 a(n) = 1 + Sum_{k=0..n-1} binomial(k+2,3) * a(k) * a(n-1-k).
%F A385875 G.f. A(x) satisfies A(x) = 1/( (1 - x) * ( 1 - x*Sum_{k=1..3} binomial(2,k-1) * x^k/k! * (d^k/dx^k A(x)) ) ).
%o A385875 (PARI) a_vector(n) = my(v=vector(n+1)); for(i=0, n, v[i+1]=1+sum(j=0, i-1, binomial(j+2, 3)*v[j+1]*v[i-j])); v;
%Y A385875 Cf. A143917, A385874, A385876, A385877.
%Y A385875 Cf. A385841.
%K A385875 nonn
%O A385875 0,3
%A A385875 _Seiichi Manyama_, Jul 11 2025