Palindromes made of only prime digits.

Terms

a(0) =2a(1) =3a(2) =5a(3) =7a(4) =22a(5) =33a(6) =55a(7) =77a(8) =222a(9) =232a(10) =252a(11) =272a(12) =323a(13) =333a(14) =353a(15) =373a(16) =525a(17) =535a(18) =555a(19) =575a(20) =727a(21) =737a(22) =757a(23) =777a(24) =2222a(25) =2332a(26) =2552a(27) =2772a(28) =3223a(29) =3333