A136419 a(n) = binomial((n+2)*(n+1),(n+1)*n).

1, 15, 924, 125970, 30045015, 11058116888, 5804731963800, 4116305022165108, 3789648142708598775, 4393971523180763714190, 6264034568006128435579200, 10768081679718351117338193075, 21964431474217462812712934302044

Offset

0,2

Links

Vincenzo Librandi, Table of n, a(n) for n = 0..200

Formula

a(n) ~ exp(2*n + 4) * n^(2*n + 3/2) / (sqrt(Pi) * 2^(2*n + 3)). - Vaclav Kotesovec, Mar 04 2018

Mathematica

Table[Binomial[(n+2)(n+1), (n+1)n], {n, 0, 20}] (* Harvey P. Dale, Nov 27 2016 *)

Prog

(Sage) [binomial(n*(n+1), 2*n) for n in range(1, 14)] # Zerinvary Lajos, Jun 01 2009
(Magma) [Binomial((n+2)*(n+1), (n+1)*n): n in [0..20]]; // Vincenzo Librandi, Mar 04 2018

Crossrefs

Sequence in context: A042747 A324423 A261067 * A231121 A103639 A055413

Adjacent sequences: A136416 A136417 A136418 * A136420 A136421 A136422

Keyword

nonn

Author

Reinhard Zumkeller, Apr 13 2008

Status

approved