Palindromic hexagonal numbers.

Terms

a(0) =0a(1) =1a(2) =6a(3) =66a(4) =3003a(5) =5995a(6) =15051a(7) =66066a(8) =617716a(9) =828828a(10) =1269621a(11) =1680861a(12) =5073705a(13) =5676765a(14) =1264114621a(15) =5289009825a(16) =6172882716a(17) =13953435931