A167869 a(n) = 4^n * Sum_{k=0..n} binomial(2*k,k)^3 / 4^k.

1, 12, 264, 9056, 379224, 17519904, 858968640, 43860112128, 2307187351512, 124161781334048, 6803252453289408, 378260174003539200, 21287072393719585216, 1210206988807094340864, 69402141007670673363456

Offset

0,2

Comments

The expression a(n) = B^n*Sum_{k=0..n} binomial(2*k,k)/B^k gives A006134 for B=1, A082590 (B=2), A132310 (B=3), A002457 (B=4), A144635 (B=5), A167713 (B=16).

The expression a(n) = B^n*Sum_{k=0..n} binomial(2*k,k)^3/B^k gives A079727 for B=1, A167867 (B=2), A167868 (B=3), A167869 (B=4), A167870 (B=16), A167871 (B=64).

Links

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

Formula

a(n) = 4^n * Sum_{k=0..n} binomial(2*k,k)^3 / 4^k.

Recurrence: n^3*a(n) = 4*(17*n^3 - 24*n^2 + 12*n - 2)*a(n-1) - 32*(2*n-1)^3*a(n-2). - Vaclav Kotesovec, Aug 13 2013

a(n) ~ 2^(6*n+4)/(15*(Pi*n)^(3/2)). - Vaclav Kotesovec, Aug 13 2013

Mathematica

Table[4^n Sum[Binomial[2k, k]^3/4^k, {k, 0, n}], {n, 0, 30}] (* Vincenzo Librandi, Mar 26 2012 *)

Crossrefs

Cf. A079727, A167867, A167868, A167869, A167870, A167872.

Cf. A000984, A066796, A006134, A082590, A132310, A002457, A144635, A167713, A167859.

Sequence in context: A113672 A259269 A035265 * A068271 A068283 A003390

Adjacent sequences: A167866 A167867 A167868 * A167870 A167871 A167872

Keyword

nonn

Author

Alexander Adamchuk, Nov 14 2009

Extensions

More terms from Sean A. Irvine, Apr 27 2010

Status

approved