A379160 G.f. A(x) satisfies A(x) = (1 + x^4) * (1 + x*A(x)^3).

1, 1, 3, 12, 56, 277, 1449, 7872, 43978, 251049, 1457910, 8585724, 51152973, 307770236, 1867362978, 11412645576, 70194232585, 434157164246, 2698676669337, 16849393604484, 105621663128839, 664493496025485, 4194246946152171, 26553277765995984, 168567628890184974, 1072818569798746567

Offset

0,3

Links

Table of n, a(n) for n=0..25.

Formula

a(n) = Sum_{k=0..floor(n/4)} binomial(3*n-12*k+1,k) * binomial(3*n-12*k+1,n-4*k)/(3*n-12*k+1).

Prog

(PARI) a(n) = sum(k=0, n\4, binomial(3*n-12*k+1, k)*binomial(3*n-12*k+1, n-4*k)/(3*n-12*k+1));

Crossrefs

Cf. A200725, A364336, A379159.

Cf. A364330.

Sequence in context: A185630 A284843 A107318 * A176281 A050147 A259800

Adjacent sequences: A379157 A379158 A379159 * A379161 A379162 A379163

Keyword

nonn

Author

Seiichi Manyama, Dec 17 2024

Status

approved