A108457 Number of partitions of (n,n) into pairs (i,j) with i>0, j>=0.

1, 1, 3, 8, 23, 60, 161, 404, 1011, 2440, 5804, 13462, 30798, 69082, 152862, 333094, 716781, 1522534, 3198011, 6642274, 13657417, 27805917, 56097811, 112183092, 222496203, 437787036, 854936195, 1657526884, 3191478236, 6104379829, 11602006003, 21916355387

Offset: 0

Author

Christian G. Bower, Jun 03 2005

Keywords

• nonn

Comments

(a,b)+(x,y)=(a+x,b+y); unit is (0,0).

Examples

			(2,2)=(1,2)+(1,0)=(1,1)+(1,1), so a(2)=3.
		

Links

• Alois P. Heinz, Table of n, a(n) for n = 0..99

Crossrefs

Main diagonal of A108456.

Cf. A000041, A091438, A108461.

Formula

a(n) = A091438(2n,n). - Alois P. Heinz, Sep 24 2018