A096191 a(n) = Sum_{k=1..n} C(n,k)^3 where C(n,k) is binomial(n,k).

1, 9, 55, 345, 2251, 15183, 104959, 739161, 5280931, 38165259, 278415919, 2046924399, 15148345759, 112738423359, 843126957055, 6332299624281, 47737325577619, 361077477684435, 2739270870994735, 20836827035351595

Offset

1,2

Links

Vincenzo Librandi, Table of n, a(n) for n = 1..200

Formula

a(n) ~ 2^(3*n+1) / (sqrt(3)*Pi*n). - Vaclav Kotesovec, Nov 27 2017

Mathematica

Table[Sum[Binomial[n, k]^3, {k, n}], {n, 20}] (* Harvey P. Dale, Jul 19 2011 *)

Crossrefs

Equals A000172(n) - 1.

Sequence in context: A362365 A183805 A037578 * A362088 A281454 A174711

Adjacent sequences: A096188 A096189 A096190 * A096192 A096193 A096194

Keyword

nonn

Author

Gerald McGarvey, Jul 25 2004

Status

approved