A366041 Expansion of (1/x) * Series_Reversion( x*(1-x)*(1-x^4) ).

1, 1, 2, 5, 15, 48, 160, 549, 1930, 6919, 25200, 92976, 346757, 1305140, 4951216, 18912245, 72675114, 280761670, 1089800270, 4248149795, 16623209911, 65273370720, 257115465600, 1015719256200, 4023178881540, 15974388769653, 63570826294760

Offset

0,3

Links

Table of n, a(n) for n=0..26.

Formula

a(n) = (1/(n+1)) * Sum_{k=0..floor(n/4)} binomial(n+k,n) * binomial(2*n-4*k,n).

Prog

(PARI) a(n) = sum(k=0, n\4, binomial(n+k, n)*binomial(2*n-4*k, n))/(n+1);

Crossrefs

Cf. A006013, A063020, A063030, A366042.

Cf. A366023.

Sequence in context: A268407 A261003 A365268 * A372532 A218251 A203067

Adjacent sequences: A366038 A366039 A366040 * A366042 A366043 A366044

Keyword

nonn

Author

Seiichi Manyama, Sep 26 2023

Status

approved