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.

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

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

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

Adjacent sequences: A231131 A231132 A231133 * A231135 A231136 A231137

Keyword

nonn

Author

R. H. Hardin, Nov 04 2013

Status

approved