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A366592
G.f. A(x) satisfies A(x) = 1 + x^4*(1+x)^2*A(x)^3.
4
1, 0, 0, 0, 1, 2, 1, 0, 3, 12, 18, 12, 15, 72, 180, 240, 235, 512, 1552, 3080, 4123, 5810, 13825, 33200, 58813, 85932, 151578, 346920, 726897, 1242234, 2025177, 3952704, 8509875, 16525872, 28565064, 50849280, 102266019, 208932438, 391951131, 699037248, 1313756457
OFFSET
0,6
FORMULA
a(n) = Sum_{k=0..floor(n/4)} binomial(2*k,n-4*k) * binomial(3*k,k)/(2*k+1).
PROG
(PARI) a(n) = sum(k=0, n\4, binomial(2*k, n-4*k)*binomial(3*k, k)/(2*k+1));
CROSSREFS
KEYWORD
nonn
AUTHOR
Seiichi Manyama, Oct 14 2023
STATUS
approved