Number of ways to reciprocally link elements of an n X 3 array either to themselves or to exactly one horizontal, vertical or antidiagonal neighbor.

A220548

Number of ways to reciprocally link elements of an n X 3 array either to themselves or to exactly one horizontal, vertical or antidiagonal neighbor.

Terms

    a(0) =3a(1) =29a(2) =224a(3) =1814a(4) =14556a(5) =117022a(6) =940432a(7) =7558245a(8) =60744605a(9) =488197825a(10) =3923590632a(11) =31533457665a(12) =253430854415

External references