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

A220725

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

Terms

    a(0) =1a(1) =1a(2) =1a(3) =1a(4) =2a(5) =1a(6) =1a(7) =7a(8) =4a(9) =1a(10) =1a(11) =21a(12) =30a(13) =8a(14) =1a(15) =1a(16) =68a(17) =230a(18) =126a(19) =16a(20) =1a(21) =1a(22) =221a(23) =1819a(24) =2586a(25) =534a(26) =32a(27) =1a(28) =1a(29) =717

External references