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

A220683

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

Terms

    a(0) =1a(1) =12a(2) =94a(3) =745a(4) =5851a(5) =46027a(6) =362057a(7) =2847943a(8) =22401961a(9) =176214299a(10) =1386105209a(11) =10903131303a(12) =85764249269a(13) =674623302927

External references