2^n-th palindromic number.

Terms

a(0) =1a(1) =2a(2) =4a(3) =8a(4) =77a(5) =232a(6) =555a(7) =2992a(8) =15751a(9) =41314a(10) =92529a(11) =1049401a(12) =3097903a(13) =7193917a(14) =63855836a(15) =227696722a(16) =555373555a(17) =3107337013a(18) =16214541261a(19) =42428982424a(20) =94857775849