Palindromes of form k*(k+6).

Terms

a(0) =0a(1) =7a(2) =55a(3) =616a(4) =19591a(5) =76167a(6) =515515a(7) =749947a(8) =7474747a(9) =72999927a(10) =236799997632a(11) =769437734967