|
|
A208122
|
|
Number of 7Xn 0..1 arrays avoiding 0 0 0 and 0 1 0 horizontally and 0 0 1 and 0 1 1 vertically
|
|
1
|
|
|
20, 400, 1260, 3969, 34713, 303601, 1432600, 6760000, 45648200, 308248249, 1680152229, 9157915809, 56635398540, 350250912400, 2009057864020, 11524062773521, 69120684953057, 414582008296369, 2421339816495600
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
1,1
|
|
COMMENTS
|
|
|
LINKS
|
|
|
FORMULA
|
Empirical: a(n) = a(n-1) -12*a(n-2) +55*a(n-3) +805*a(n-4) +900*a(n-5) +10320*a(n-6) -123840*a(n-8) -129600*a(n-9) -1391040*a(n-10) -1140480*a(n-11) +2985984*a(n-12) -2985984*a(n-13) +35831808*a(n-14)
|
|
EXAMPLE
|
Some solutions for n=4
..0..0..1..1....0..0..1..1....0..0..1..1....1..1..1..1....1..1..0..0
..1..0..1..1....1..0..0..1....1..1..1..1....0..1..1..1....0..0..1..1
..0..0..1..1....0..0..1..1....0..0..1..1....0..1..1..1....1..1..0..0
..1..0..1..1....1..0..0..1....1..1..0..0....0..0..1..1....0..0..1..1
..0..0..1..1....0..0..1..1....0..0..1..1....0..1..1..0....1..1..0..0
..1..0..0..1....1..0..0..1....1..1..0..0....0..0..1..1....0..0..1..1
..0..0..1..1....0..0..1..1....0..0..1..1....0..1..1..0....1..1..0..0
|
|
CROSSREFS
|
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
|
|
STATUS
|
approved
|
|
|
|