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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. 1
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 (list; graph; refs; listen; history; text; internal format)
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

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Last modified May 22 02:18 EDT 2022. Contains 353933 sequences. (Running on oeis4.)