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A253439 Number of (5+1) X (n+1) 0..1 arrays with every 2 X 2 subblock diagonal minus antidiagonal sum nondecreasing horizontally, vertically and ne-to-sw antidiagonally. 1
181, 180, 193, 228, 300, 444, 732, 1308, 2460, 4764, 9372, 18588, 37020, 73884, 147612, 295068, 589980, 1179804, 2359452, 4718748, 9437340, 18874524, 37748892, 75497628, 150995100, 301990044, 603979932, 1207959708, 2415919260, 4831838364 (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) + 156 for n>3.

Empirical g.f.: x*(181 - 363*x + 15*x^2 + 9*x^3 + 2*x^4) / ((1 - x)*(1 - 2*x)). - Colin Barker, Dec 12 2018

EXAMPLE

Some solutions for n=4:

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

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

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

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

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

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

CROSSREFS

Row 5 of A253435.

Sequence in context: A036200 A253432 A218977 * A175789 A157747 A253156

Adjacent sequences:  A253436 A253437 A253438 * A253440 A253441 A253442

KEYWORD

nonn

AUTHOR

R. H. Hardin, Dec 31 2014

STATUS

approved

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Last modified December 5 17:28 EST 2021. Contains 349557 sequences. (Running on oeis4.)