Palindromes of form k^2 + k + 3.

Terms

a(0) =3a(1) =5a(2) =9a(3) =33a(4) =383a(5) =555a(6) =3663a(7) =5115a(8) =30803a(9) =32223a(10) =34043a(11) =59295a(12) =567765a(13) =5912195a(14) =37877873a(15) =534141435a(16) =957747759a(17) =5356556535a(18) =5646996465a(19) =53205650235a(20) =56511511565a(21) =358023320853