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A231134
Number of (n+1) X (2+1) black-square subarrays of 0..2 arrays with no element equal to a strict majority of its diagonal and antidiagonal neighbors, with values 0..2 introduced in row major order.
1
2, 9, 40, 182, 808, 3688, 16368, 74728, 331648, 1514160, 6719936, 30680320, 136161152, 621652928, 2758934016, 12596099456, 55902265856, 255225567744, 1132706802688, 5171449356800, 22951211032576, 104785303002112
OFFSET
1,1
LINKS
FORMULA
Empirical: a(n) = 22*a(n-2) - 36*a(n-4) + 16*a(n-6).
Empirical g.f.: x*(2 + 9*x - 4*x^2 - 16*x^3 + 8*x^5) / (1 - 22*x^2 + 36*x^4 - 16*x^6). - Colin Barker, Sep 26 2018
EXAMPLE
Some solutions for n=5:
..x..0..x....x..0..x....x..0..x....x..0..x....x..0..x....x..0..x....x..0..x
..1..x..2....1..x..0....1..x..2....1..x..1....0..x..1....0..x..1....1..x..2
..x..1..x....x..2..x....x..1..x....x..2..x....x..1..x....x..2..x....x..0..x
..0..x..0....0..x..0....0..x..1....1..x..1....2..x..0....2..x..0....1..x..2
..x..1..x....x..2..x....x..0..x....x..2..x....x..2..x....x..1..x....x..0..x
..2..x..0....1..x..0....2..x..2....0..x..0....0..x..0....2..x..0....2..x..2
CROSSREFS
Column 2 of A231137.
Sequence in context: A020728 A107979 A021001 * A370479 A038112 A268039
KEYWORD
nonn
AUTHOR
R. H. Hardin, Nov 04 2013
STATUS
approved