A168543 pi(n-th single or isolated number).

1, 2, 3, 5, 7, 9, 10, 12, 13, 15, 16, 17, 19, 20, 22, 23, 24, 25, 26, 28, 30, 31, 32, 33, 35, 37, 38, 39, 40, 41, 43, 45, 47, 48, 49, 51, 52, 54, 55, 56, 57, 59, 60, 62, 63, 64, 66, 67, 68, 69, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 83, 85, 86, 87, 88, 89, 91, 92, 93, 94

Offset: 1

Author

Juri-Stepan Gerasimov, Nov 29 2009

Keywords

• nonn

Formula

a(n)=A000720(A167706(n)).

Extensions

Corrected (25 inserted) by R. J. Mathar, Nov 30 2009