A220600 Number of ways to reciprocally link elements of an nX6 array either to themselves or to exactly two horizontal, vertical and antidiagonal neighbors, without 3-loops.

1, 117, 25747, 3174778, 352586943, 41011388731, 4807269151250, 561355035745825, 65523075831128720, 7650441027984730028, 893266330737712903338, 104295209452828358545715, 12177239947634323813819907

Offset: 1

Author

R. H. Hardin Dec 16 2012

Keywords

• nonn

Comments

Column 6 of A220602

Examples

			Some solutions for n=3 0=self 2=n 3=ne 4=w 6=e 7=sw 8=s (reciprocal directions total 10)
.00.78.00.67.46.47...00.78.78.78.78.00...00.78.78.00.78.78...00.00.68.48.00.00
.38.26.34.78.38.00...38.23.23.23.26.47...38.23.27.37.23.28...68.48.26.24.67.47
.26.46.34.26.24.00...26.46.46.46.34.00...26.34.36.46.46.24...26.24.00.36.34.00
		

Links

• R. H. Hardin, Table of n, a(n) for n = 1..210