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 A376135 #7 Oct 05 2024 18:05:35
%S A376135 1,1,-2,-15,86,1030,-9844,-156219,2098406,41282298,-716119260,
%T A376135 -16837011158,358425572604,9820300812556,-247923816153128,
%U A376135 -7765514675946195,226869417798485382,8001626352728559218,-265582398152349968716,-10419379442081103988738
%N A376135 a(0) = 1; a(n) = Sum_{k=0..n-1} (-1)^k * (2*k+1) * a(k) * a(n-k-1).
%F A376135 G.f. A(x) satisfies: A(x) = 1 / (1 - x * A(-x) + 2 * x^2 * A'(-x)).
%t A376135 a[0] = 1; a[n_] := a[n] = Sum[(-1)^k (2 k + 1) a[k] a[n - k - 1], {k, 0, n - 1}]; Table[a[n], {n, 0, 19}]
%t A376135 nmax = 19; A[_] = 0; Do[A[x_] = 1/(1 - x A[-x] + 2 x^2 A'[-x]) + O[x]^(nmax + 1) // Normal, nmax + 1]; CoefficientList[A[x], x]
%Y A376135 Cf. A000699, A090192, A105523, A376134, A376137.
%K A376135 sign
%O A376135 0,3
%A A376135 _Ilya Gutkovskiy_, Sep 11 2024