Number of primitive (aperiodic) palindromic structures using a maximum of six 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) =202a(12) =197a(13) =875a(14) =861a(15) =4105a(16) =4096a(17) =20647a(18) =20593a(19) =109298a(20) =109246a(21) =601476a(22) =601289a(23) =3403126a(24) =3402911a(25) =19628059a(26) =19627188a(27) =114700263a(28) =114699438a(29) =676207627