Numbers with exactly 2 odd integers in their Collatz (or 3x+1) trajectory.

Terms

a(0) =5a(1) =10a(2) =20a(3) =21a(4) =40a(5) =42a(6) =80a(7) =84a(8) =85a(9) =160a(10) =168a(11) =170a(12) =320a(13) =336a(14) =340a(15) =341a(16) =640a(17) =672a(18) =680a(19) =682a(20) =1280a(21) =1344a(22) =1360a(23) =1364a(24) =1365a(25) =2560a(26) =2688a(27) =2720a(28) =2728a(29) =2730