Number of ways to reciprocally link elements of an n X 2 array either to themselves or to exactly two king-move neighbors, without consecutive collinear links.

A220713

Number of ways to reciprocally link elements of an n X 2 array either to themselves or to exactly two king-move neighbors, without consecutive collinear links.

Terms

    a(0) =1a(1) =8a(2) =26a(3) =118a(4) =463a(5) =1930a(6) =7843a(7) =32209a(8) =131698a(9) =539466a(10) =2208130a(11) =9041065a(12) =37013388a(13) =151537869a(14) =620403077a(15) =2539982216a(16) =10398860814a(17) =42573713750a(18) =174299854287a(19) =713596365222

External references