A253157 Number of (n+1) X (6+1) 0..1 arrays with every 2 X 2 subblock diagonal minus antidiagonal sum nondecreasing horizontally and vertically.

325, 336, 345, 380, 452, 596, 884, 1460, 2612, 4916, 9524, 18740, 37172, 74036, 147764, 295220, 590132, 1179956, 2359604, 4718900, 9437492, 18874676, 37749044, 75497780, 150995252, 301990196, 603980084, 1207959860, 2415919412, 4831838516

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) + 308 for n>3.

Empirical g.f.: x*(325 - 639*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....0..1..1..1..1..1..1
..0..0..0..0..0..0..0....1..1..1..1..1..1..1....1..1..1..1..1..1..1
..1..1..1..1..1..1..1....1..1..1..1..1..1..1....0..0..0..0..0..0..0
..0..0..0..0..0..0..0....1..1..1..1..1..1..1....1..1..1..1..1..1..1
..1..1..1..1..1..1..1....0..0..0..0..0..0..0....0..0..0..0..0..0..0
..1..1..1..1..1..1..1....0..0..0..0..0..0..0....1..1..1..1..1..1..1
..0..0..0..0..0..0..1....0..0..0..0..0..0..0....0..0..0..0..0..0..1

Crossrefs

Column 6 of A253159.

Sequence in context: A159976 A253433 A253440 * A184036 A159844 A000443

Adjacent sequences: A253154 A253155 A253156 * A253158 A253159 A253160

Keyword

nonn

Author

R. H. Hardin, Dec 28 2014

Status

approved