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A231067 Number of black 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, 3, 4, 11, 15, 42, 57, 161, 218, 617, 835, 2364, 3199, 9057, 12256, 34699, 46955, 132938, 179893, 509309, 689202, 1951253, 2640455, 7475596, 10116051, 28640333, 38756384, 109726191, 148482575, 420380482, 568863057, 1610552121, 2179415178 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..210

FORMULA

Empirical: a(n) = 5*a(n-2) - 5*a(n-4) + 2*a(n-6).

Empirical g.f.: x*(1 + 3*x - x^2 - 4*x^3 + 2*x^5) / (1 - 5*x^2 + 5*x^4 - 2*x^6). - Colin Barker, Sep 26 2018

EXAMPLE

Some solutions for n=4:

..x..0..x....x..0..x....x..0..x....x..0..x....x..0..x....x..0..x....x..0..x

..1..x..1....0..x..1....1..x..1....1..x..0....1..x..0....1..x..1....1..x..1

..x..1..x....x..1..x....x..0..x....x..1..x....x..1..x....x..0..x....x..0..x

..0..x..0....0..x..1....1..x..0....1..x..0....0..x..1....0..x..0....0..x..1

..x..1..x....x..0..x....x..1..x....x..0..x....x..0..x....x..1..x....x..1..x

CROSSREFS

Column 2 of A231070.

Sequence in context: A042483 A002530 A042709 * A042327 A046114 A116654

Adjacent sequences:  A231064 A231065 A231066 * A231068 A231069 A231070

KEYWORD

nonn

AUTHOR

R. H. Hardin, Nov 03 2013

STATUS

approved

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Last modified July 8 03:38 EDT 2020. Contains 335504 sequences. (Running on oeis4.)