|
|
A209648
|
|
Number of n X 6 0..1 arrays avoiding 0 0 1 and 1 0 0 horizontally and 0 0 1 and 1 0 1 vertically.
|
|
1
|
|
|
22, 484, 2354, 7128, 16830, 34012, 61754, 103664, 163878, 247060, 358402, 503624, 688974, 921228, 1207690, 1556192, 1975094, 2473284, 3060178, 3745720, 4540382, 5455164, 6501594, 7691728, 9038150, 10553972, 12252834, 14148904, 16256878
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
1,1
|
|
COMMENTS
|
|
|
LINKS
|
|
|
FORMULA
|
Empirical: a(n) = 22*n^4 + (88/3)*n^3 - 22*n^2 - (22/3)*n.
G.f.: 22*x*(1 + 17*x + 7*x^2 - x^3) / (1 - x)^5.
a(n) = 5*a(n-1) - 10*a(n-2) + 10*a(n-3) - 5*a(n-4) + a(n-5) for n>5.
(End)
|
|
EXAMPLE
|
Some solutions for n=4:
..0..1..0..1..1..0....0..1..0..1..1..0....1..1..1..0..1..0....1..0..1..1..1..0
..1..0..1..0..1..1....0..0..0..0..0..0....0..0..0..0..0..0....1..1..0..1..1..1
..0..0..0..0..0..0....0..0..0..0..0..0....0..0..0..0..0..0....1..1..0..1..0..1
..0..0..0..0..0..0....0..0..0..0..0..0....0..0..0..0..0..0....1..1..0..1..0..1
|
|
CROSSREFS
|
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
|
|
STATUS
|
approved
|
|
|
|