Number of primitive (aperiodic) palindromic structures using a maximum of five different symbols.

Terms

a(0) =1a(1) =1a(2) =0a(3) =1a(4) =1a(5) =4a(6) =3a(7) =14a(8) =13a(9) =50a(10) =47a(11) =201a(12) =196a(13) =854a(14) =840a(15) =3839a(16) =3830a(17) =18001a(18) =17947a(19) =86471a(20) =86419a(21) =421989a(22) =421803a(23) =2079474a(24) =2079260a(25) =10306747a(26) =10305897a(27) =51263890a(28) =51263086a(29) =255514354