Number of reversible strings with n labeled beads of 2 colors.

A032107

Number of reversible strings with n labeled beads of 2 colors.

Terms

    a(0) =2a(1) =4a(2) =24a(3) =192a(4) =1920a(5) =23040a(6) =322560a(7) =5160960a(8) =92897280a(9) =1857945600a(10) =40874803200a(11) =980995276800

External references