A366082 Expansion of (1/x) * Series_Reversion( x*(1-x)^3/(1-x-x^2) ).

1, 2, 6, 21, 79, 308, 1219, 4826, 18857, 71574, 257553, 837114, 2140496, 1379550, -35589730, -370646635, -2719034151, -17429175486, -103771133876, -588804389677, -3225403649859, -17180039158530, -89342552789741, -454604059204324, -2265246385921936

Offset

0,2

Links

Seiichi Manyama, Table of n, a(n) for n = 0..1000

Formula

a(n) = (1/(n+1)) * Sum_{k=0..floor(n/2)} (-1)^k * binomial(n+1,k) * binomial(3*n-k+1,n-2*k).

Prog

(PARI) a(n) = sum(k=0, n\2, (-1)^k*binomial(n+1, k)*binomial(3*n-k+1, n-2*k))/(n+1);

Crossrefs

Cf. A007440, A108623, A366081, A366083.

Cf. A366049.

Sequence in context: A150195 A363810 A150196 * A148491 A026737 A111279

Adjacent sequences: A366079 A366080 A366081 * A366083 A366084 A366085

Keyword

sign

Author

Seiichi Manyama, Sep 28 2023

Status

approved