A054087 s(3n-2), s=A054086; also a bisection of A003511.
1, 4, 6, 9, 12, 15, 17, 20, 23, 25, 28, 31, 34, 36, 39, 42, 45, 47, 50, 53, 56, 58, 61, 64, 66, 69, 72, 75, 77, 80, 83, 86, 88, 91, 94, 96, 99, 102, 105, 107, 110, 113, 116, 118, 121, 124, 127, 129, 132, 135, 137, 140, 143, 146, 148, 151
Offset: 1