T(n,k)=Number of ways to reciprocally link elements of an nXk array either to themselves or to exactly two horizontal, vertical or antidiagonal neighbors.

A220688

T(n,k)=Number of ways to reciprocally link elements of an nXk array either to themselves or to exactly two horizontal, vertical or antidiagonal neighbors.

Terms

    a(0) =1a(1) =1a(2) =1a(3) =1a(4) =4a(5) =1a(6) =1a(7) =12a(8) =12a(9) =1a(10) =1a(11) =37a(12) =94a(13) =37a(14) =1a(15) =1a(16) =114a(17) =745a(18) =745a(19) =114a(20) =1a(21) =1a(22) =351a(23) =5851a(24) =15452a(25) =5851a(26) =351a(27) =1a(28) =1a(29) =1081

External references