login

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).

A221250
Number of n X n arrays of occupancy after each element moves to some horizontal or antidiagonal neighbor, with no occupancy greater than 2
0
0, 4, 30, 58081, 78633756, 4919350997521, 720107530988047980, 2283974100099963226425600
OFFSET
1,2
COMMENTS
Diagonal of A221255
EXAMPLE
Some solutions for n=3
..0..2..0....1..2..0....0..2..0....1..2..0....0..2..1....1..2..1....0..2..1
..2..2..0....1..2..0....1..2..0....0..2..1....1..2..0....0..2..0....1..2..1
..1..2..0....1..2..0....2..2..0....1..2..0....1..2..0....0..2..1....0..2..0
CROSSREFS
Sequence in context: A365366 A201974 A376765 * A119926 A103307 A196248
KEYWORD
nonn
AUTHOR
R. H. Hardin Jan 06 2013
STATUS
approved