Number of ways to reciprocally link elements of an 3Xn array either to themselves or to exactly two horizontal, diagonal and antidiagonal neighbors, without consecutive collinear links.

A220740

Number of ways to reciprocally link elements of an 3Xn array either to themselves or to exactly two horizontal, diagonal and antidiagonal neighbors, without consecutive collinear links.

Terms

    a(0) =1a(1) =4a(2) =22a(3) =103a(4) =487a(5) =2276a(6) =10653a(7) =49951a(8) =234006a(9) =1096844a(10) =5140867a(11) =24096269a(12) =112943160a(13) =529386957a(14) =2481335981a(15) =11630503852a(16) =54514395378a(17) =255519475371

External references