A253155 Number of (n+1) X (4+1) 0..1 arrays with every 2 X 2 subblock diagonal minus antidiagonal sum nondecreasing horizontally and vertically.

109, 120, 129, 164, 236, 380, 668, 1244, 2396, 4700, 9308, 18524, 36956, 73820, 147548, 295004, 589916, 1179740, 2359388, 4718684, 9437276, 18874460, 37748828, 75497564, 150995036, 301989980, 603979868, 1207959644, 2415919196, 4831838300

Offset

1,1

Links

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

Formula

Empirical: a(n) = 3*a(n-1) - 2*a(n-2) for n>5.

Empirical: a(n) = 9*2^(n-1) + 92 for n>3.

Empirical g.f.: x*(109 - 207*x - 13*x^2 + 17*x^3 + 2*x^4) / ((1 - x)*(1 - 2*x)). - Colin Barker, Dec 09 2018

Example

Some solutions for n=6:
..0..1..1..1..1....0..0..0..0..0....1..0..0..0..1....0..0..0..1..0
..0..0..0..0..0....1..1..1..1..1....1..0..0..0..1....1..0..0..1..0
..1..1..1..1..1....1..1..1..1..1....1..0..0..0..1....1..0..0..1..0
..1..1..1..1..1....1..1..1..1..1....1..0..0..0..1....1..0..0..1..0
..0..0..0..0..0....0..0..0..0..0....1..0..0..0..1....1..0..0..1..0
..0..0..0..0..0....1..1..1..1..1....1..0..0..0..1....1..0..0..1..0
..0..0..0..0..1....0..0..0..0..0....1..0..0..0..1....1..0..0..1..1

Crossrefs

Column 4 of A253159.

Sequence in context: A196673 A159027 A039492 * A095609 A046295 A164288

Adjacent sequences: A253152 A253153 A253154 * A253156 A253157 A253158

Keyword

nonn

Author

R. H. Hardin, Dec 28 2014

Status

approved