Palindromic in bases 6 and 15.

Terms

a(0) =0a(1) =1a(2) =2a(3) =3a(4) =4a(5) =5a(6) =7a(7) =14a(8) =80a(9) =160a(10) =301a(11) =602a(12) =693a(13) =994a(14) =1295a(15) =1627a(16) =1777a(17) =2365a(18) =2666a(19) =5296a(20) =5776a(21) =6256a(22) =17360a(23) =34720a(24) =51301a(25) =52201a(26) =105092a(27) =155493a(28) =209284a(29) =587846