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A253344 Number of (n+1) X (2+1) 0..1 arrays with every 2 X 2 subblock diagonal maximum minus antidiagonal maximum nondecreasing horizontally, vertically and ne-to-sw antidiagonally. 1

%I

%S 47,173,735,3192,13917,60779,265605,1161035,5075841,22191959,97027389,

%T 424226867,1854830841,8109825551,35458405365,155034056747,

%U 677852377137,2963761021319,12958396425645,56657753602595,247723635757161

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

%H R. H. Hardin, <a href="/A253344/b253344.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 6*a(n-1) - 5*a(n-2) - 12*a(n-3) + 12*a(n-4) for n>6.

%F Empirical g.f.: x*(47 - 109*x - 68*x^2 + 211*x^3 - 48*x^4 - 19*x^5) / ((1 - x)*(1 - 2*x)*(1 - 3*x - 6*x^2)). - _Colin Barker_, Dec 11 2018

%e Some solutions for n=4:

%e ..1..1..1....0..1..1....1..1..1....0..1..1....0..1..1....0..1..0....0..0..0

%e ..0..0..0....0..0..1....1..1..1....1..1..0....1..1..0....0..1..1....1..1..1

%e ..1..1..1....1..1..1....1..1..0....0..1..0....1..1..1....0..1..0....0..1..0

%e ..1..0..0....1..1..1....0..1..0....1..1..1....1..1..0....1..1..0....1..1..0

%e ..1..0..1....1..1..0....1..1..1....0..0..1....0..1..1....0..0..1....1..1..1

%Y Column 2 of A253350.

%K nonn

%O 1,1

%A _R. H. Hardin_, Dec 30 2014

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Last modified February 2 02:30 EST 2023. Contains 359997 sequences. (Running on oeis4.)