A186120 Number of (n+1) X 2 binary arrays with every 2 X 2 subblock diagonal sum less antidiagonal sum equal to some horizontal or vertical neighbor 2 X 2 subblock diagonal sum less antidiagonal sum.

0, 14, 18, 50, 74, 182, 298, 678, 1186, 2566, 4690, 9830, 18498, 38006, 72914, 147974, 287554, 579222, 1135282, 2276710, 4488226, 8978102, 17768850, 35496326, 70442882, 140631254, 279616498, 558094758, 1111168738, 2217823222, 4420075090

Offset

1,2

Comments

Column 1 of A186128.

Links

R. H. Hardin, Table of n, a(n) for n = 1..200

Formula

Empirical: a(n) = 3*a(n-1) - 6*a(n-3) + 6*a(n-4) - 4*a(n-5) for n>6.

Empirical g.f.: 2*x^2*(7 - 12*x - 2*x^2 + 4*x^3 - 8*x^4) / ((1 - 2*x)*(1 - x - 2*x^2 + 2*x^3 - 2*x^4)). - Colin Barker, Apr 17 2018

Example

Some solutions for 3 X 2:
..0..1....1..1....1..0....0..0....1..1....0..0....1..0....1..0....0..1....0..1
..0..0....0..0....1..1....1..1....0..0....0..0....0..0....1..0....0..1....1..1
..1..0....1..1....0..1....0..0....0..0....1..1....0..1....1..0....0..1....1..0

Crossrefs

Cf. A186128.

Sequence in context: A244034 A154864 A328239 * A065343 A222576 A165228

Adjacent sequences: A186117 A186118 A186119 * A186121 A186122 A186123

Keyword

nonn

Author

R. H. Hardin, Feb 13 2011

Status

approved