Number of reversible strings with n labeled beads of 3 colors.

A032108

Number of reversible strings with n labeled beads of 3 colors.

Terms

    a(0) =3a(1) =9a(2) =81a(3) =972a(4) =14580a(5) =262440a(6) =5511240a(7) =132269760a(8) =3571283520a(9) =107138505600

External references