Digit '6' concatenated with a(n) is a lucky number.

Terms

a(0) =3a(1) =7a(2) =9a(3) =13a(4) =15a(5) =19a(6) =21a(7) =31a(8) =39a(9) =43a(10) =45a(11) =51a(12) =55a(13) =73a(14) =79a(15) =85a(16) =93a(17) =99a(18) =111a(19) =115a(20) =123a(21) =141a(22) =147a(23) =159a(24) =163a(25) =175a(26) =177a(27) =195a(28) =211a(29) =229