Digit '5' concatenated with n is a lucky number.

Terms

a(0) =1a(1) =11a(2) =17a(3) =19a(4) =29a(5) =35a(6) =37a(7) =41a(8) =53a(9) =59a(10) =77a(11) =79a(12) =83a(13) =91a(14) =103a(15) =127a(16) =137a(17) =139a(18) =149a(19) =151a(20) =157a(21) =169a(22) =179a(23) =181a(24) =191a(25) =211a(26) =217a(27) =229a(28) =233a(29) =235