login
A186160
1/4 the number of n X n 0..3 arrays with every element equal to exactly one or two of its horizontal and vertical neighbors
0
0, 7, 702, 751266, 5033988714, 268995986029278
OFFSET
1,2
COMMENTS
Diagonal of A186168
EXAMPLE
Some solutions for 4X4 with a(1,1)=0
..0..2..0..2....0..0..2..0....0..2..1..1....0..0..2..2....0..2..2..1
..0..2..0..2....0..0..2..0....0..2..0..0....0..2..1..2....0..0..0..1
..1..2..3..3....2..3..3..3....2..1..1..0....2..2..1..0....2..3..3..1
..1..1..1..1....2..3..2..2....2..2..1..0....3..3..3..0....2..3..0..0
CROSSREFS
Sequence in context: A163016 A261696 A174855 * A129291 A229149 A159815
KEYWORD
nonn
AUTHOR
R. H. Hardin Feb 13 2011
STATUS
approved