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A230983 Number of white square subarrays of (n+1) X (2+1) binary arrays with no element equal to a strict majority of its diagonal and antidiagonal neighbors, with upper left element zero. 1
1, 1, 4, 5, 15, 20, 57, 77, 218, 295, 835, 1130, 3199, 4329, 12256, 16585, 46955, 63540, 179893, 243433, 689202, 932635, 2640455, 3573090, 10116051, 13689141, 38756384, 52445525, 148482575, 200928100, 568863057, 769791157, 2179415178, 2949206335 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,3
LINKS
FORMULA
Empirical: a(n) = 5*a(n-2) - 5*a(n-4) + 2*a(n-6).
Empirical g.f.: x*(1 + x - x^2) / (1 - 5*x^2 + 5*x^4 - 2*x^6). - Colin Barker, Sep 25 2018
EXAMPLE
Some solutions for n=6:
..0..x..0....0..x..0....0..x..0....0..x..0....0..x..0....0..x..0....0..x..0
..x..1..x....x..1..x....x..1..x....x..1..x....x..1..x....x..1..x....x..1..x
..0..x..0....0..x..0....0..x..0....1..x..0....0..x..1....1..x..1....0..x..1
..x..0..x....x..0..x....x..1..x....x..0..x....x..0..x....x..0..x....x..0..x
..1..x..1....1..x..1....1..x..1....1..x..0....1..x..0....1..x..0....1..x..1
..x..1..x....x..0..x....x..0..x....x..1..x....x..1..x....x..1..x....x..0..x
..0..x..0....1..x..1....1..x..1....0..x..0....0..x..0....0..x..0....1..x..1
CROSSREFS
Column 2 of A230989.
Sequence in context: A066516 A047184 A002509 * A100234 A007390 A037955
KEYWORD
nonn
AUTHOR
R. H. Hardin, Nov 02 2013
STATUS
approved

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Last modified February 22 19:58 EST 2024. Contains 370260 sequences. (Running on oeis4.)