A167887 n-th single or isolated number plus n-th non-single or nonisolated number.

2, 5, 9, 17, 25, 31, 39, 47, 53, 60, 67, 75, 83, 89, 98, 103, 110, 119, 126, 133, 139, 154, 159, 167, 181, 189, 196, 201, 208, 216, 230, 237, 251, 264, 271, 277, 285, 297, 305, 312, 320, 328, 334, 347, 362, 368, 374, 389, 396, 409, 415, 422, 431, 438, 445, 451

Offset: 1

Author

Juri-Stepan Gerasimov, Nov 14 2009

Keywords

• nonn

Examples

			a(1)=2+0=2, a(2)=4+1=5, a(3)=6+3=9, a(4)=12+5=17.
		

Crossrefs

Cf. A167706, A167707.

Formula

a(n)=A167706(n)+A167707(n).

Extensions

All terms > 110 corrected by R. J. Mathar, May 30 2010