A178610 n-th semiprime minus difference between the prime indices of the two factors of n-th semiprime.

4, 5, 9, 8, 11, 14, 19, 18, 25, 21, 30, 28, 34, 31, 35, 38, 49, 46, 53, 51, 49, 52, 62, 62, 63, 76, 70, 81, 73, 79, 89, 84, 80, 90, 91, 101, 109, 102, 116, 121, 105, 112, 117, 129, 116, 128, 123, 142, 138, 126, 147, 137, 145, 156, 144, 169, 162, 155, 167, 176, 185, 170

Offset: 1

Author

Juri-Stepan Gerasimov, May 30 2010

Keywords

• nonn

Formula

a(n)=A001358(n)-A176506(n).

Extensions

Corrected (153 replaced by 155) by R. J. Mathar, May 31 2010