Number of reversible strings with n labeled beads of 3 colors, no palindromes of more than 1 bead.

A032070

Number of reversible strings with n labeled beads of 3 colors, no palindromes of more than 1 bead.

Terms

    a(0) =3a(1) =6a(2) =54a(3) =864a(4) =12960a(5) =252720a(6) =5307120a(7) =130636800a(8) =3527193600a(9) =106697606400

External references