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

A056325

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

Terms

    a(0) =1a(1) =1a(2) =2a(3) =4a(4) =11a(5) =32a(6) =117a(7) =467a(8) =2135a(9) =10480a(10) =55091a(11) =301633a(12) =1704115a(13) =9819216a(14) =57365191a(15) =338134521a(16) =2005134639a(17) =11937364184a(18) =71254895955a(19) =426063226937

External references