Palindromes of form n(n+3).

Terms

a(0) =0a(1) =4a(2) =88a(3) =868a(4) =4554a(5) =8008a(6) =45154a(7) =89698a(8) =452254a(9) =4526254a(10) =8996998a(11) =830333038a(12) =862626268a(13) =899969998a(14) =4058008504a(15) =45032023054a(16) =45229592254a(17) =89999699998a(18) =405485584504