A253433 Number of (n+1) X (6+1) 0..1 arrays with every 2 X 2 subblock diagonal minus antidiagonal sum nondecreasing horizontally, vertically and ne-to-sw antidiagonally.

325, 318, 336, 372, 444, 588, 876, 1452, 2604, 4908, 9516, 18732, 37164, 74028, 147756, 295212, 590124, 1179948, 2359596, 4718892, 9437484, 18874668, 37749036, 75497772, 150995244, 301990188, 603980076, 1207959852, 2415919404, 4831838508

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>3.

Empirical: a(n) = 9*2^(n-1) + 300 for n>1.

Empirical g.f.: x*(325 - 657*x + 32*x^2) / ((1 - x)*(1 - 2*x)). - Colin Barker, Dec 12 2018

Example

Some solutions for n=4:
..1..1..1..1..1..0..1....1..0..1..1..0..1..0....0..1..1..1..1..1..1
..1..1..1..1..1..0..1....1..0..1..1..0..1..0....1..1..1..1..1..1..1
..1..1..1..1..1..0..1....1..0..1..1..0..1..0....1..1..1..1..1..1..1
..1..1..1..1..1..0..1....1..0..1..1..0..1..0....1..1..1..1..1..1..1
..1..1..1..1..1..0..1....1..0..1..1..0..1..1....1..1..1..1..1..1..1

Crossrefs

Column 6 of A253435.

Sequence in context: A172198 A343080 A159976 * A253440 A253157 A184036

Adjacent sequences: A253430 A253431 A253432 * A253434 A253435 A253436

Keyword

nonn

Author

R. H. Hardin, Dec 31 2014

Status

approved