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

1,1

Comments

Column 4 of A186168

Links

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

Example

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

Crossrefs

Sequence in context: A227673 A203479 A034226 * A159492 A368619 A368369

Adjacent sequences: A186160 A186161 A186162 * A186164 A186165 A186166

Keyword

nonn

Author

R. H. Hardin Feb 13 2011

Status

approved