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A231125
Number of (n+1) X (2+1) white-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, 8, 40, 176, 808, 3584, 16368, 72640, 331648, 1471872, 6719936, 29823488, 136161152, 604291584, 2758934016, 12244319232, 55902265856, 248097701888, 1132706802688, 5027022614528, 22951211032576, 101858889359360
OFFSET
1,1
LINKS
FORMULA
Empirical: a(n) = 22*a(n-2) - 36*a(n-4) + 16*a(n-6).
Empirical g.f.: 2*x*(1 + 4*x - 2*x^2) / (1 - 22*x^2 + 36*x^4 - 16*x^6). - Colin Barker, Sep 26 2018
EXAMPLE
Some solutions for n=5:
..0..x..1....0..x..0....0..x..1....0..x..0....0..x..1....0..x..0....0..x..1
..x..2..x....x..1..x....x..2..x....x..1..x....x..2..x....x..1..x....x..2..x
..1..x..2....2..x..0....2..x..0....0..x..2....1..x..2....1..x..1....0..x..0
..x..1..x....x..1..x....x..1..x....x..0..x....x..1..x....x..2..x....x..2..x
..2..x..0....2..x..0....2..x..0....2..x..0....0..x..0....2..x..0....0..x..2
..x..2..x....x..0..x....x..0..x....x..2..x....x..2..x....x..0..x....x..0..x
CROSSREFS
Column 2 of A231131.
Sequence in context: A003445 A181326 A220964 * A221587 A186947 A071007
KEYWORD
nonn
AUTHOR
R. H. Hardin, Nov 04 2013
STATUS
approved