Number of ways to reciprocally link elements of an nX4 array either to themselves or to exactly two horizontal, diagonal and antidiagonal neighbors, without consecutive collinear links.

A220734

Number of ways to reciprocally link elements of an nX4 array either to themselves or to exactly two horizontal, diagonal and antidiagonal neighbors, without consecutive collinear links.

Terms

    a(0) =1a(1) =13a(2) =103a(3) =712a(4) =5760a(5) =45421a(6) =355883a(7) =2807273a(8) =22112517a(9) =174154372a(10) =1371967416a(11) =10807412577a(12) =85133340257a(13) =670628304993

External references