Number of achiral color patterns (set partitions) for a row or loop of length n using exactly 3 colors (sets).

A304973

Number of achiral color patterns (set partitions) for a row or loop of length n using exactly 3 colors (sets).

Terms

    a(0) =0a(1) =0a(2) =0a(3) =1a(4) =2a(5) =5a(6) =10a(7) =19a(8) =38a(9) =65a(10) =130a(11) =211a(12) =422a(13) =665a(14) =1330a(15) =2059a(16) =4118a(17) =6305a(18) =12610a(19) =19171a(20) =38342a(21) =58025a(22) =116050a(23) =175099a(24) =350198a(25) =527345a(26) =1054690a(27) =1586131a(28) =3172262a(29) =4766585

External references