|
|
A202041
|
|
Number of zero-sum nX2 -1..1 arrays with every element unequal to at most two horizontal and vertical neighbors
|
|
1
|
|
|
3, 19, 73, 335, 1593, 7669, 37311, 184335, 919889, 4620477, 23332387, 118371541, 602858159, 3080279011, 15782030681, 81053501795, 417143999201, 2150782607289, 11107401645291, 57445755808701, 297487456185331, 1542374070100235
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
1,1
|
|
COMMENTS
|
|
|
LINKS
|
|
|
EXAMPLE
|
Some solutions for n=7
..0..1....0..1...-1.-1....1..0...-1..0...-1..0....1.-1....1..1...-1..1....1..1
.-1.-1....1..1...-1.-1....0..0....1..0....1..1...-1..1...-1..1...-1..0....0.-1
..1..1....0..0....1.-1...-1.-1....1..0...-1.-1...-1..1...-1..1...-1..0....0.-1
..0..0....0..0....1..0....1..1....1..0....1.-1...-1..0....1..1....0..0....1..1
..1.-1....0.-1....1..0....0..1...-1.-1....1.-1....0..0...-1.-1....0..1....1.-1
..1.-1...-1.-1....1..1....0..0...-1.-1....1.-1....0..0...-1.-1....0..1...-1.-1
.-1..0....0..0....0..0...-1.-1....1..1....0..1....0..1....0..0...-1..1....0..0
|
|
CROSSREFS
|
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
|
|
STATUS
|
approved
|
|
|
|