A366070 Expansion of (1/x) * Series_Reversion( x*(1+x-x^2)/(1+x)^5 ).

1, 4, 23, 155, 1143, 8932, 72682, 609348, 5227035, 45659020, 404756300, 3632075109, 32928392154, 301152242600, 2775117150576, 25741623112539, 240162703635495, 2252187478291088, 21217451539791085, 200709823787548845, 1905712342347978340

Offset

0,2

Links

Table of n, a(n) for n=0..20.

Formula

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

Prog

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

Crossrefs

Cf. A045743, A049125, A279565.

Sequence in context: A055723 A364478 A271469 * A374564 A007297 A263843

Adjacent sequences: A366067 A366068 A366069 * A366071 A366072 A366073

Keyword

nonn

Author

Seiichi Manyama, Sep 29 2023

Status

approved