A366042 Expansion of (1/x) * Series_Reversion( x*(1-x)*(1-x^5) ).

1, 1, 2, 5, 14, 43, 139, 465, 1595, 5577, 19805, 71240, 259037, 950590, 3516110, 13095440, 49068051, 184839543, 699607625, 2659276675, 10147039881, 38853068780, 149240187330, 574913637375, 2220609902199, 8598120578442, 33366877654697, 129758691426484

Offset: 0

Author

Seiichi Manyama, Sep 26 2023

Keywords

• nonn

Crossrefs

Cf. A006013, A063020, A063030, A366041.

Cf. A366024.

Programs

PARI

a(n) = sum(k=0, n\5, binomial(n+k, n)*binomial(2*n-5*k, n))/(n+1);

Formula

a(n) = (1/(n+1)) * Sum_{k=0..floor(n/5)} binomial(n+k,n) * binomial(2*n-5*k,n).