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.

2, 8, 40, 176, 808, 3584, 16368, 72640, 331648, 1471872, 6719936, 29823488, 136161152, 604291584, 2758934016, 12244319232, 55902265856, 248097701888, 1132706802688, 5027022614528, 22951211032576, 101858889359360

Offset: 1

Author

R. H. Hardin, Nov 04 2013

Keywords

• nonn

Examples

			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
		

Links

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

Crossrefs

Column 2 of A231131.

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