login
A120380
Number of partitions of n*(n+1).
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
FORMULA
a(n) = A000041(A002378(n)). - Michel Marcus, Sep 30 2024
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);
MATHEMATICA
Table[PartitionsP[n*(n+1)], {n, 0, 21}] (* James C. McMahon, Sep 30 2024 *)
PROG
(PARI) a(n)=numbpart(n^2+n) /* Michael Somos, Jul 24 2006 */
CROSSREFS
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