A072331 a(n) = 2^(n-1) * Sum_{k=0..n} ((n+k)!/(n-k)!)/k!.

3, 38, 772, 21768, 786736, 34703456, 1807726656, 108602413184, 7392195003136, 562241229891072, 47257832090862592, 4349969517278922752, 435185983056255725568, 47017486048144734052352

Offset

1,1

Links

Table of n, a(n) for n=1..14.

Mathematica

Table[2^(n-1) Sum[((n+k)!/(n-k)!)/k!, {k, 0, n}], {n, 15}] (* Harvey P. Dale, May 22 2012 *)

Crossrefs

Cf. A001517.

Sequence in context: A005780 A033678 A228697 * A109518 A300631 A300627

Adjacent sequences: A072328 A072329 A072330 * A072332 A072333 A072334

Keyword

easy,nonn

Author

Benoit Cloitre, Jul 31 2002

Extensions

Definition clarified by Harvey P. Dale, May 22 2012

Status

approved