Composite numbers whose prime factors contain no digits other than 2 and 5.

Terms

a(0) =4a(1) =8a(2) =10a(3) =16a(4) =20a(5) =25a(6) =32a(7) =40a(8) =50a(9) =64a(10) =80a(11) =100a(12) =125a(13) =128a(14) =160a(15) =200a(16) =250a(17) =256a(18) =320a(19) =400a(20) =500a(21) =512a(22) =625a(23) =640a(24) =800a(25) =1000a(26) =1024a(27) =1250a(28) =1280a(29) =1600