A095814 Number of nonisomorphic partitions of n on the Ferrers diagram.

1, 1, 1, 2, 3, 4, 6, 8, 11, 15, 21, 28, 39, 51, 68, 88, 116, 149, 193, 245, 314, 396, 501, 628, 788, 979, 1218, 1505, 1859, 2283, 2802, 3421, 4175, 5072, 6155, 7442, 8989, 10819, 13008, 15593, 18669, 22292, 26587, 31631, 37588, 44567, 52779, 62377

Offset

0,4

Comments

Partitions of n into at most ceiling(n/2) parts and with at least 1 part greater than or equal to n - floor(n/2).

Links

Table of n, a(n) for n=0..47.

Formula

a(n) = A000041(n)/2 if A000041(n) is even and (A000041(n)+1)/2 if A000041(n) is odd.

Example

a(5) = 4 because the 4 nonisomorphic partitions of 5 are (5), (4,1), (3,2), (3,1,1).

Prog

(PARI)

Crossrefs

Sequence in context: A188917 A046935 A241334 * A006683 A014213 A341218

Adjacent sequences: A095811 A095812 A095813 * A095815 A095816 A095817

Keyword

nonn

Author

Jon Perry, Jul 13 2004

Status

approved