Palindromic in bases 10 and 20.

Terms

a(0) =0a(1) =1a(2) =2a(3) =3a(4) =4a(5) =5a(6) =6a(7) =7a(8) =8a(9) =9a(10) =11a(11) =252a(12) =6556a(13) =6776a(14) =7117a(15) =10101a(16) =12621a(17) =20202a(18) =22722a(19) =30303a(20) =1784871a(21) =1786871a(22) =1788871a(23) =1913191a(24) =1915191a(25) =1917191a(26) =1919191a(27) =1444884441a(28) =334495594433a(29) =334843348433