Numbers of form 4^i*5^j, with i, j >= 0.

Terms

a(0) =1a(1) =4a(2) =5a(3) =16a(4) =20a(5) =25a(6) =64a(7) =80a(8) =100a(9) =125a(10) =256a(11) =320a(12) =400a(13) =500a(14) =625a(15) =1024a(16) =1280a(17) =1600a(18) =2000a(19) =2500a(20) =3125a(21) =4096a(22) =5120a(23) =6400a(24) =8000a(25) =10000a(26) =12500a(27) =15625a(28) =16384a(29) =20480