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A364597
G.f. satisfies A(x) = 1/(1-x) + x^3*(1-x)*A(x)^5.
3
1, 1, 1, 2, 5, 11, 26, 71, 197, 540, 1521, 4401, 12826, 37597, 111385, 332861, 1000181, 3021071, 9174308, 27987989, 85712801, 263438881, 812394661, 2512807846, 7793552386, 24233089051, 75526196851, 235897169106, 738271145577, 2314825565700, 7270693111431
OFFSET
0,4
FORMULA
a(n) = Sum_{k=0..floor(n/3)} binomial(n,3*k) * binomial(5*k,k) / (4*k+1).
PROG
(PARI) a(n) = sum(k=0, n\3, binomial(n, 3*k)*binomial(5*k, k)/(4*k+1));
CROSSREFS
Sequence in context: A319760 A343872 A000664 * A242766 A182580 A067922
KEYWORD
nonn,easy
AUTHOR
Seiichi Manyama, Jul 29 2023
STATUS
approved