Numbers of the form 2^k or 5*2^k.

Terms

a(0) =1a(1) =2a(2) =4a(3) =5a(4) =8a(5) =10a(6) =16a(7) =20a(8) =32a(9) =40a(10) =64a(11) =80a(12) =128a(13) =160a(14) =256a(15) =320a(16) =512a(17) =640a(18) =1024a(19) =1280a(20) =2048a(21) =2560a(22) =4096a(23) =5120a(24) =8192a(25) =10240a(26) =16384a(27) =20480a(28) =32768a(29) =40960