A120380 Number of partitions of n*(n+1).

1, 2, 11, 77, 627, 5604, 53174, 526823, 5392783, 56634173, 607163746, 6620830889, 73232243759, 819876908323, 9275102575355, 105882246722733, 1218374349844333, 14118662665280005, 164637479165761044, 1930656072350465812, 22755290216580025259, 269435605212954994471

Offset

0,2

Links

Table of n, a(n) for n=0..21.

Henry Bottomley, Partition and composition calculator.

G. P. Michon, Partition Function

Example

a(2)=11 because the number of partitions of 6 is 11.

Maple

with(combinat); [seq(numbpart(n*(n+1)), n=1..20)];
with(combinat): seq(numbpart(n*(n+1)), n=0..21);

Prog

(PARI) a(n)=numbpart(n^2+n) /* Michael Somos, Jul 24 2006 */

Crossrefs

Cf. A003107, A002378.

Sequence in context: A110329 A221844 A006766 * A369542 A079266 A094569

Adjacent sequences: A120377 A120378 A120379 * A120381 A120382 A120383

Keyword

nonn

Author

Zerinvary Lajos, Jun 29 2006

Extensions

Edited by Michael Somos, Emeric Deutsch and N. J. A. Sloane, Jul 23 2006

Status

approved