A026184 a(n) = (1/3)*s(n), where s(n) is the n-th multiple of 3 in A026136.

1, 3, 5, 2, 7, 9, 11, 4, 13, 15, 17, 6, 19, 21, 23, 8, 25, 27, 29, 10, 31, 33, 35, 12, 37, 39, 41, 14, 43, 45, 47, 16, 49, 51, 53, 18, 55, 57, 59, 20, 61, 63, 65, 22, 67, 69, 71, 24, 73, 75, 77, 26, 79, 81, 83, 28, 85, 87, 89, 30, 91, 93, 95