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A363581
G.f. satisfies A(x) = exp( Sum_{k>=1} A(x^k) * x^k/(k * (1 + 3*x^k)) ).
4
1, 1, -1, 4, -6, 11, -22, 62, -151, 353, -867, 2261, -5861, 15178, -39878, 106099, -283823, 763248, -2065453, 5621318, -15368682, 42190539, -116281176, 321647511, -892617214, 2484583934, -6935203356, 19408586888, -54447145335, 153084848495
OFFSET
0,4
FORMULA
A(x) = (1 + 3*x) * B(x) where B(x) is the g.f. of A363579.
a(n) = A363579(n) + 3*A363579(n-1) for n > 0.
PROG
(PARI) seq(n) = my(A=1); for(i=1, n, A=exp(sum(k=1, i, subst(A, x, x^k)*x^k/(k*(1+3*x^k)))+x*O(x^n))); Vec(A);
CROSSREFS
KEYWORD
sign
AUTHOR
Seiichi Manyama, Jun 10 2023
STATUS
approved