Number of periodic palindromic structures of length n using a maximum of two different symbols.

Terms

a(0) =1a(1) =2a(2) =2a(3) =4a(4) =4a(5) =7a(6) =8a(7) =14a(8) =16a(9) =26a(10) =32a(11) =51a(12) =64a(13) =100a(14) =128a(15) =198a(16) =256a(17) =392a(18) =512a(19) =778a(20) =1024a(21) =1552a(22) =2048a(23) =3091a(24) =4096a(25) =6176a(26) =8192a(27) =12324a(28) =16384a(29) =24640