A186163 1/4 the number of nX4 0..3 arrays with every element equal to exactly one or two of its horizontal and vertical neighbors.

4, 321, 14364, 751266, 37402872, 1899336597, 95752776009, 4840082975532, 244420512852030, 12347377339339755, 623671780419814416, 31503432697236966789, 1591300459563274835532, 80380228276030331585859

Offset: 1

Author

R. H. Hardin Feb 13 2011

Keywords

• nonn

Comments

Column 4 of A186168

Examples

			Some solutions for 6X4 with a(1,1)=0
..0..0..0..1....0..0..2..2....0..0..0..3....0..0..1..1....0..0..3..3
..0..2..2..1....0..2..2..1....0..2..2..3....0..2..2..1....0..2..2..2
..0..0..2..3....0..0..1..1....0..0..3..0....0..0..1..1....0..0..3..1
..2..0..0..3....2..0..2..2....2..0..3..0....2..0..3..3....2..0..3..1
..2..2..0..0....2..3..3..1....2..2..2..0....2..2..2..2....2..0..2..2
..0..0..2..2....0..0..0..1....0..0..1..1....0..0..1..1....2..2..0..0
		

Links

• R. H. Hardin, Table of n, a(n) for n = 1..200