Digit '3' concatenated with a(n) is a lucky number.

Terms

a(0) =1a(1) =3a(2) =7a(3) =19a(4) =21a(5) =27a(6) =31a(7) =39a(8) =49a(9) =57a(10) =61a(11) =67a(12) =85a(13) =91a(14) =93a(15) =99a(16) =109a(17) =111a(18) =121a(19) =123a(20) =133a(21) =153a(22) =163a(23) =171a(24) =175a(25) =183a(26) =187a(27) =199a(28) =213a(29) =223