A383526 - OEIS

The OEIS is supported by the many generous donors to the OEIS Foundation.

A383526

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

1

1, 1, 1, 4, 17, 46, 112, 365, 1297, 4126, 12686, 41647, 141440, 470887, 1553021, 5205769, 17665105, 59858038, 202599814, 689183087, 2355887902, 8065291637, 27637715887, 94924591313, 326810899744, 1126888746871, 3890420726167, 13450563963085, 46571447873597

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

OFFSET

0,4

COMMENTS

Diagonal of the rational function 1 / ((1-x)*(1-y)*(1-z) - x*y^3*z^3).

LINKS

Table of n, a(n) for n=0..28.

PROG

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

CROSSREFS

Cf. A000172, A248658, A383525.

Sequence in context: A147656 A095667 A212577 * A332863 A119949 A213499

Adjacent sequences: A383523 A383524 A383525 * A383527 A383528 A383529

KEYWORD

nonn

AUTHOR

Seiichi Manyama, Apr 29 2025

STATUS

approved