A366049 - OEIS

A366049

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

1, 2, 8, 39, 211, 1218, 7349, 45790, 292361, 1902834, 12577737, 84205212, 569788192, 3890728052, 26775751320, 185525538183, 1293171205833, 9061500578178, 63794947215218, 451028012126797, 3200898741338041, 22794860112273294, 162841330273522907

(list; graph; refs; listen; history; text; internal format)

OFFSET

0,2

LINKS

Table of n, a(n) for n=0..22.

FORMULA

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

PROG

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

CROSSREFS

Cf. A005043, A109081, A366050.

Sequence in context: A112737 A206901 A162476 * A218321 A236339 A292100

Adjacent sequences: A366046 A366047 A366048 * A366050 A366051 A366052

KEYWORD

nonn

AUTHOR

Seiichi Manyama, Sep 27 2023

STATUS

approved