Palindromic and divisible by 3.

Terms

a(0) =0a(1) =3a(2) =6a(3) =9a(4) =33a(5) =66a(6) =99a(7) =111a(8) =141a(9) =171a(10) =222a(11) =252a(12) =282a(13) =303a(14) =333a(15) =363a(16) =393a(17) =414a(18) =444a(19) =474a(20) =525a(21) =555a(22) =585a(23) =606a(24) =636a(25) =666a(26) =696a(27) =717a(28) =747a(29) =777