a(n) = 8*n + 7. Or, numbers whose binary expansion ends in 111.

Terms

a(0) =7a(1) =15a(2) =23a(3) =31a(4) =39a(5) =47a(6) =55a(7) =63a(8) =71a(9) =79a(10) =87a(11) =95a(12) =103a(13) =111a(14) =119a(15) =127a(16) =135a(17) =143a(18) =151a(19) =159a(20) =167a(21) =175a(22) =183a(23) =191a(24) =199a(25) =207a(26) =215a(27) =223a(28) =231a(29) =239