A242842 Number of compositions of n with difference 2 between the number of odd parts and the number of even parts, both counted without multiplicity.

2, 3, 6, 11, 20, 25, 41, 85, 148, 355, 751, 1701, 3756, 8255, 17513, 37038, 76349, 156618, 317591, 639142, 1279302, 2546711, 5057675, 10010975, 19788607, 39058684, 77055159, 151930328, 299600229, 590849561, 1165782514, 2301229945, 4545782370, 8985884632

Offset: 4

Author

Alois P. Heinz, May 23 2014

Keywords

• nonn

Examples

			a(4) = 2: [1,3], [3,1].
a(5) = 3: [1,1,3], [1,3,1], [3,1,1].
a(6) = 6: [1,1,1,3], [1,1,3,1], [1,3,1,1], [3,1,1,1], [1,5], [5,1].
		

Links

• Alois P. Heinz, Table of n, a(n) for n = 4..500

Crossrefs

Column k=2 of A242626.