Largest palindromic substring in 2^n.

Terms

a(0) =1a(1) =2a(2) =4a(3) =8a(4) =6a(5) =3a(6) =6a(7) =8a(8) =6a(9) =5a(10) =4a(11) =8a(12) =9a(13) =9a(14) =8a(15) =8a(16) =55a(17) =131a(18) =262a(19) =242a(20) =8a(21) =9a(22) =9a(23) =838a(24) =777a(25) =55a(26) =88a(27) =77a(28) =545a(29) =9