A168350 Sum of first n non-single or nonisolated numbers.

0, 1, 4, 9, 16, 24, 33, 43, 54, 67, 81, 96, 112, 129, 148, 168, 189, 211, 235, 260, 286, 313, 341, 370, 401, 433, 466, 500, 535, 571, 609, 648, 688, 729, 772, 816, 861, 907, 955, 1004, 1054, 1105, 1157, 1211, 1266, 1322, 1379, 1437, 1496, 1557, 1619, 1682

Offset: 1

Author

Juri-Stepan Gerasimov, Nov 23 2009

Keywords

• nonn

Examples

			a(1)=0, a(2)=0+1=1, a(3)=0+1+3=4.
		

Crossrefs

Cf. A167707.

Formula

a(n)=sum{j=1..n} A167707(j).

Extensions

Formula and A-number corrected and entries checked by R. J. Mathar, Nov 24 2009