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 A385984 #10 Jul 14 2025 10:03:31
%S A385984 1,1,-1,-9,57,1353,-38313,-2796417,339169041,90178580529,
%T A385984 -45316930884849,-46917802526957721,95533688640942728073,
%U A385984 392558870984301366092217,-3210372581644929567134113497,-52647023496165910533698485658193,1724296469950918188679460249845485729
%N A385984 a(0) = 1; a(n) = Sum_{k=0..n-1} (-2)^k * binomial(n-1,k) * a(k) * a(n-1-k).
%F A385984 E.g.f. A(x) satisfies A'(x) = A(x) * A(-2*x).
%o A385984 (PARI) a_vector(n) = my(v=vector(n+1)); v[1]=1; for(i=1, n, v[i+1]=sum(j=0, i-1, (-2)^j*binomial(i-1, j)*v[j+1]*v[i-j])); v;
%Y A385984 Cf. A000142, A126444, A155585, A385983.
%K A385984 sign
%O A385984 0,4
%A A385984 _Seiichi Manyama_, Jul 14 2025