A026216 (1/3)*s(n), where s(n) is the n-th multiple of 3 in A026177.

1, 4, 2, 3, 10, 12, 5, 16, 6, 7, 22, 8, 9, 28, 30, 11, 34, 36, 13, 40, 14, 15, 46, 48, 17, 52, 18, 19, 58, 20, 21, 64, 66, 23, 70, 24, 25, 76, 26, 27, 82, 84, 29, 88, 90, 31, 94, 32, 33, 100, 102, 35, 106, 108, 37, 112, 38, 39, 118, 120, 41