|
|
A191507
|
|
Number of n X n symmetric binary matrices with each 1 adjacent to no more than 2 horizontally or vertically neighboring 1s
|
|
1
|
|
|
2, 8, 52, 646, 14570, 599702, 45191945, 6225542127, 1567856872728, 722008623925586, 607932060252871024, 935917819388424802645, 2634499346573878930718088, 13559220442178025486399949918
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
1,1
|
|
LINKS
|
|
|
EXAMPLE
|
Some solutions for n=4
..1..0..0..1....0..1..0..1....1..1..0..0....0..0..1..0....1..0..1..0
..0..1..1..1....1..1..0..0....1..1..0..1....0..0..0..0....0..0..1..1
..0..1..0..0....0..0..0..0....0..0..0..0....1..0..0..1....1..1..0..1
..1..1..0..0....1..0..0..0....0..1..0..1....0..0..1..0....0..1..1..0
|
|
CROSSREFS
|
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
|
|
STATUS
|
approved
|
|
|
|