A368933 Expansion of (1/x) * Series_Reversion( x * (1-x) * (1-x-x^5) ).

1, 2, 7, 30, 143, 729, 3891, 21471, 121505, 701316, 4112751, 24435424, 146773582, 889813460, 5437598036, 33459382065, 207138653334, 1289231982454, 8062548100445, 50637167131635, 319255808742145, 2019867936975125, 12819928874057325, 81603361510347675

Offset

0,2

Links

Table of n, a(n) for n=0..23.

Formula

a(n) = (1/(n+1)) * Sum_{k=0..floor(n/5)} binomial(n+k,k) * binomial(3*n-4*k+1,n-5*k).

Prog

(PARI) a(n) = sum(k=0, n\5, binomial(n+k, k)*binomial(3*n-4*k+1, n-5*k))/(n+1);
(PARI) my(N=30, x='x+O('x^N)); Vec(serreverse(x*(1-x)*(1-x-x^5))/x)

Crossrefs

Cf. A236339, A368931, A368932.

Cf. A276989, A366112.

Sequence in context: A046648 A006013 A358965 * A187979 A358964 A366055

Adjacent sequences: A368930 A368931 A368932 * A368934 A368935 A368936

Keyword

nonn

Author

Seiichi Manyama, Jan 10 2024

Status

approved