|
|
A208284
|
|
Number of n X 5 0..1 arrays avoiding 0 0 0 and 0 0 1 horizontally and 0 0 1 and 1 1 0 vertically.
|
|
1
|
|
|
16, 256, 1260, 3984, 9900, 21096, 40376, 71360, 118584, 187600, 285076, 418896, 598260, 833784, 1137600, 1523456, 2006816, 2604960, 3337084, 4224400, 5290236, 6560136, 8061960, 9825984, 11885000, 14274416, 17032356, 20199760, 23820484
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
1,1
|
|
COMMENTS
|
|
|
LINKS
|
|
|
FORMULA
|
Empirical: a(n) = (5/6)*n^5 + 9*n^4 + (91/6)*n^3 - 9*n^2.
G.f.: 4*x*(2 - x)*(2 + 21*x + 6*x^2 - 4*x^3) / (1 - x)^6.
a(n) = 6*a(n-1) - 15*a(n-2) + 20*a(n-3) - 15*a(n-4) + 6*a(n-5) - a(n-6) for n>6.
(End)
|
|
EXAMPLE
|
Some solutions for n=4:
..0..1..0..1..0....0..1..0..1..0....0..1..0..1..1....1..0..1..1..1
..1..0..1..0..0....1..1..0..1..1....0..1..0..1..0....0..1..0..1..1
..1..1..0..1..0....1..1..0..1..0....0..1..0..1..0....0..1..1..1..1
..1..1..0..1..0....1..1..0..1..0....0..1..0..1..0....0..1..1..1..1
|
|
CROSSREFS
|
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
|
|
STATUS
|
approved
|
|
|
|