login
A221398
Number of nX4 arrays of occupancy after each element moves to some horizontal, diagonal or antidiagonal neighbor, with no 2-loops and with no occupancy greater than 2
1
0, 56, 2110, 89173, 3658806, 149231797, 6054851040, 244978992940, 9895703526545, 399360021773713, 16108509055841956, 649556971613873720, 26188220092197924807, 1055730681220332762888, 42557554894233839425159
OFFSET
1,2
COMMENTS
Column 4 of A221400
LINKS
EXAMPLE
Some solutions for n=3
..0..2..2..0....0..2..1..1....1..2..2..1....0..0..2..1....0..1..0..1
..1..2..2..0....1..1..1..0....0..1..2..0....0..2..2..0....1..1..2..0
..1..1..0..1....1..2..2..0....0..2..1..0....0..2..2..1....1..2..2..1
CROSSREFS
Sequence in context: A004387 A111597 A111781 * A280803 A124101 A198948
KEYWORD
nonn
AUTHOR
R. H. Hardin Jan 15 2013
STATUS
approved