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A253153 Number of (n+1) X (2+1) 0..1 arrays with every 2 X 2 subblock diagonal minus antidiagonal sum nondecreasing horizontally and vertically. 1
39, 72, 88, 120, 192, 336, 624, 1200, 2352, 4656, 9264, 18480, 36912, 73776, 147504, 294960, 589872, 1179696, 2359344, 4718640, 9437232, 18874416, 37748784, 75497520, 150994992, 301989936, 603979824, 1207959600, 2415919152, 4831838256 (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) + 48 for n>3.

Empirical g.f.: x*(39 - 45*x - 50*x^2 + 8*x^4) / ((1 - x)*(1 - 2*x)). - Colin Barker, Dec 09 2018

EXAMPLE

Some solutions for n=6:

..0..1..1....1..1..1....0..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....0..0..0....0..0..0

..1..1..1....0..0..0....1..0..0....1..1..1....1..1..1....1..1..1....1..1..1

..0..0..0....1..1..1....1..0..0....0..0..0....0..0..0....1..1..1....0..0..0

..0..0..0....1..1..1....1..0..0....1..1..1....1..1..1....0..0..0....1..1..1

..1..1..1....0..0..0....1..0..0....0..0..0....1..1..1....1..1..1....0..0..0

..1..1..1....0..0..0....0..0..1....0..0..0....1..1..1....0..0..1....0..0..0

CROSSREFS

Column 2 of A253159.

Sequence in context: A039467 A250657 A243577 * A044105 A044486 A072122

Adjacent sequences:  A253150 A253151 A253152 * A253154 A253155 A253156

KEYWORD

nonn

AUTHOR

R. H. Hardin, Dec 28 2014

STATUS

approved

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Last modified May 28 13:05 EDT 2022. Contains 354115 sequences. (Running on oeis4.)