A220596 - OEIS

%I #5 Dec 18 2015 18:18:24

%S 1,2,65,9047,7558495,41011388731,1417058414112748,

%T 305516864725171735943,412489181606705015322075070

%N Number of ways to reciprocally link elements of an n X n array either to themselves or to exactly two horizontal, vertical and antidiagonal neighbors, without 3-loops

%C Diagonal of A220602

%e Some solutions for n=3 0=self 2=n 3=ne 4=w 6=e 7=sw 8=s (reciprocal directions total 10)

%e .00.00.00...00.78.78...68.46.47...68.46.48...00.67.48...00.78.00...00.67.47

%e .00.67.47...38.23.28...28.36.47...28.68.24...38.67.24...38.28.00...38.37.00

%e .36.34.00...26.46.24...26.34.00...26.24.00...23.00.00...26.24.00...23.00.00

%K nonn

%O 1,2

%A _R. H. Hardin_ Dec 16 2012