Composite and every divisor (except 1) contains the digit 5.

Terms

a(0) =25a(1) =125a(2) =265a(3) =295a(4) =625a(5) =755a(6) =785a(7) =1255a(8) =1285a(9) =1325a(10) =1475a(11) =1765a(12) =1795a(13) =2285a(14) =2515a(15) =2545a(16) =2605a(17) =2615a(18) =2705a(19) =2735a(20) =2785a(21) =2815a(22) =2845a(23) =2855a(24) =2885a(25) =2935a(26) =2965a(27) =2995a(28) =3125a(29) =3265