Palindromic in bases 5 and 7.

Terms

a(0) =0a(1) =1a(2) =2a(3) =3a(4) =4a(5) =6a(6) =24a(7) =57a(8) =78a(9) =114a(10) =342a(11) =624a(12) =856a(13) =1432a(14) =10308a(15) =12654a(16) =27616a(17) =100056a(18) =537856a(19) =593836a(20) =769621a(21) =1434168a(22) =1473368a(23) =1636104a(24) =1823544a(25) =1862744a(26) =17968646a(27) =18108296a(28) =22412057a(29) =34713713