Number of chiral pairs of color patterns (set partitions) in a row of length n using exactly 4 colors (subsets).

A320527

Number of chiral pairs of color patterns (set partitions) in a row of length n using exactly 4 colors (subsets).

Terms

    a(0) =0a(1) =0a(2) =0a(3) =0a(4) =4a(5) =28a(6) =167a(7) =824a(8) =3840a(9) =16920a(10) =72655a(11) =305140a(12) =1265264a(13) =5193188a(14) =21173607a(15) =85887984a(16) =347150080a(17) =1399355440a(18) =5629755935a(19) =22615859180a(20) =90754215024a(21) =363888497148

External references