A168241 n-th squarefree number plus n-th non-single or nonisolated number.
1, 3, 6, 10, 13, 15, 19, 21, 24, 27, 29, 32, 35, 38, 41, 43, 47, 51, 54, 56, 59, 61, 63, 66, 69, 71, 74, 76, 78, 82, 85, 90, 93, 96, 100, 102, 104, 107, 110, 114, 116, 118, 121, 124, 126, 129, 131, 135, 137, 140, 144, 146, 149, 151, 153, 157, 160, 163, 165, 168, 171
Offset: 1