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 A363474 #15 Jun 05 2023 08:54:55
%S A363474 1,2,-3,-14,22,138,-213,-1536,2474,18928,-31451,-248992,420804,
%T A363474 3416514,-5844716,-48349920,83503128,700674606,-1219159874,
%U A363474 -10345673158,18109290380,155082913608,-272798814028,-2353889042848,4157686512816,36104006239798
%N A363474 G.f. satisfies A(x) = exp( 2 * Sum_{k>=1} (-1)^(k+1) * A(-x^k) * x^k/k ).
%H A363474 Seiichi Manyama, <a href="/A363474/b363474.txt">Table of n, a(n) for n = 0..1000</a>
%F A363474 A(x) = Sum_{k>=0} a(k) * x^k = Product_{k>=0} (1+x^(k+1))^(2 * (-1)^k * a(k)).
%F A363474 a(0) = 1; a(n) = (2/n) * Sum_{k=1..n} ( Sum_{d|k} d * (-1)^(d+k/d) * a(d-1) ) * a(n-k).
%o A363474 (PARI) seq(n) = my(A=1); for(i=1, n, A=exp(2*sum(k=1, i, (-1)^(k+1)*subst(A, x, -x^k)*x^k/k)+x*O(x^n))); Vec(A);
%Y A363474 Cf. A306768, A363475.
%Y A363474 Cf. A005753, A363470.
%K A363474 sign
%O A363474 0,2
%A A363474 _Seiichi Manyama_, Jun 03 2023