A253158 Number of (n+1) X (7+1) 0..1 arrays with every 2 X 2 subblock diagonal minus antidiagonal sum nondecreasing horizontally and vertically.

613, 624, 633, 668, 740, 884, 1172, 1748, 2900, 5204, 9812, 19028, 37460, 74324, 148052, 295508, 590420, 1180244, 2359892, 4719188, 9437780, 18874964, 37749332, 75498068, 150995540, 301990484, 603980372, 1207960148, 2415919700, 4831838804

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) + 596 for n>3.

Empirical g.f.: x*(613 - 1215*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..1..1..1....1..1..1..1..1..1..1..1....1..0..0..1..1..0..1..0
..0..0..0..0..0..0..0..0....0..0..0..0..0..0..0..0....1..0..0..1..1..0..1..0
..1..1..1..1..1..1..1..1....1..1..1..1..1..1..1..1....1..0..0..1..1..0..1..0
..0..0..0..0..0..0..0..0....0..0..0..0..0..0..0..0....1..0..0..1..1..0..1..0
..0..0..0..0..0..0..0..0....0..0..0..0..0..0..0..0....1..0..0..1..1..0..1..0
..1..1..1..1..1..1..1..1....1..1..1..1..1..1..1..1....1..0..0..1..1..0..1..0
..1..1..1..1..1..1..1..1....0..0..0..0..0..0..0..1....1..0..0..1..1..0..1..0

Crossrefs

Column 7 of A253159.

Sequence in context: A292036 A253434 A253441 * A159641 A100364 A142435

Adjacent sequences: A253155 A253156 A253157 * A253159 A253160 A253161

Keyword

nonn

Author

R. H. Hardin, Dec 28 2014

Status

approved