|
|
A210906
|
|
Number of n X n 0..2 symmetric matrices with every element equal to zero or two horizontal and vertical neighbors, and new values 0..2 introduced in lower triangle row major order
|
|
0
|
|
|
1, 3, 20, 258, 5316, 175508, 9246604, 778330944, 104490906936, 22379344947816, 7640730937406288, 4158457819686881368, 3606450263851909019488
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
1,2
|
|
LINKS
|
|
|
EXAMPLE
|
Some solutions for n=4
..0..1..0..1....0..1..0..1....0..1..0..1....0..1..1..2....0..1..0..1
..1..2..1..0....1..0..1..2....1..2..1..0....1..1..1..0....1..0..2..2
..0..1..0..2....0..1..2..1....0..1..2..1....1..1..2..2....0..2..2..2
..1..0..2..0....1..2..1..0....1..0..1..2....2..0..2..2....1..2..2..1
|
|
CROSSREFS
|
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
|
|
STATUS
|
approved
|
|
|
|