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A366501
G.f. A(x) satisfies A(x) = 1 + x / ((1+x)^4*A(x)^3).
6
1, 1, -7, 49, -399, 3633, -35511, 363937, -3858079, 41951521, -465296487, 5243459409, -59865074223, 690979478481, -8049598938135, 94522387901505, -1117615459764031, 13294669980012865, -158995530738069703, 1910555096402418545, -23056131790988675279
OFFSET
0,3
FORMULA
G.f.: A(x) = 1/B(-x) where B(x) is the g.f. of A213336.
a(n) = (-1)^(n-1) * Sum_{k=0..n} binomial(n+3*k-1,n-k) * binomial(4*k-1,k) / (4*k-1).
PROG
(PARI) a(n) = (-1)^(n-1)*sum(k=0, n, binomial(n+3*k-1, n-k)*binomial(4*k-1, k)/(4*k-1));
KEYWORD
sign
AUTHOR
Seiichi Manyama, Oct 11 2023
STATUS
approved