Number of reversible string structures with n beads using a maximum of five different colors.

A056324

Number of reversible string structures with n beads using a maximum of five different colors.

Terms

    a(0) =1a(1) =1a(2) =2a(3) =4a(4) =11a(5) =32a(6) =116a(7) =455a(8) =1993a(9) =9134a(10) =43580a(11) =211659a(12) =1041441a(13) =5156642a(14) =25640456a(15) =127773475a(16) =637624313a(17) =3184387574a(18) =15910947980a(19) =79521737939a(20) =397510726681

External references