|
|
A183982
|
|
1/4 the number of (n+1) X 6 binary arrays with all 2 X 2 subblock sums the same.
|
|
1
|
|
|
25, 27, 30, 36, 46, 66, 102, 174, 310, 582, 1110, 2166, 4246, 8406, 16662, 33174, 66070, 131862, 263190, 525846, 1050646, 2100246, 4198422, 8394774, 16785430, 33566742, 67125270, 134242326, 268468246, 536920086, 1073807382, 2147581974, 4295098390
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
1,1
|
|
COMMENTS
|
|
|
LINKS
|
|
|
FORMULA
|
Empirical: a(n) = 3*a(n-1) - 6*a(n-3) + 4*a(n-4).
G.f.: x*(25 - 48*x - 51*x^2 + 96*x^3) / ((1 - x)*(1 - 2*x)*(1 - 2*x^2)).
a(n) = 3*2^(n/2-1) + 2^(n-1) + 22 for n even.
a(n) = 2^(n-1) + 2^((n+1)/2) + 22 for n odd.
(End)
|
|
EXAMPLE
|
Some solutions for 5 X 6:
..0..1..1..0..1..0....0..1..1..1..0..1....0..1..0..0..1..0....0..1..0..1..1..1
..1..0..0..1..0..1....1..1..0..1..1..1....1..0..1..1..0..1....1..0..1..0..0..0
..0..1..1..0..1..0....0..1..1..1..0..1....0..1..0..0..1..0....0..1..0..1..1..1
..1..0..0..1..0..1....1..1..0..1..1..1....1..0..1..1..0..1....1..0..1..0..0..0
..0..1..1..0..1..0....0..1..1..1..0..1....0..1..0..0..1..0....0..1..0..1..1..1
|
|
CROSSREFS
|
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
|
|
STATUS
|
approved
|
|
|
|