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A366240
G.f. A(x) satisfies A(x) = 1 + x + x*(1 + x)^3*A(x)^3.
2
1, 2, 9, 60, 432, 3378, 27792, 237122, 2079132, 18620709, 169614960, 1566540573, 14635978998, 138080055192, 1313596636812, 12587218990644, 121378106852988, 1176981533610012, 11469587139406515, 112265849283068877, 1103256200355696855
OFFSET
0,2
FORMULA
a(n) = Sum_{k=0..n} binomial(5*k+1,n-k) * binomial(3*k,k)/(2*k+1).
PROG
(PARI) a(n) = sum(k=0, n, binomial(5*k+1, n-k)*binomial(3*k, k)/(2*k+1));
CROSSREFS
KEYWORD
nonn
AUTHOR
Seiichi Manyama, Oct 05 2023
STATUS
approved