Divisible by 3 (and 9) and are differences between two cubes in at least one way.

Terms

a(0) =63a(1) =117a(2) =189a(3) =279a(4) =342a(5) =387a(6) =504a(7) =513a(8) =657a(9) =702a(10) =819a(11) =936a(12) =999a(13) =1197a(14) =1206a(15) =1323a(16) =1413a(17) =1512a(18) =1647a(19) =1701a(20) =1854a(21) =1899a(22) =2133a(23) =2169a(24) =2196a(25) =2232a(26) =2457a(27) =2619a(28) =2646a(29) =2736