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A250798 Number of (1+1) X (n+1) 0..1 arrays with nondecreasing min(x(i,j),x(i,j-1)) in the i direction and nondecreasing absolute value of x(i,j)-x(i-1,j) in the j direction. 1

%I

%S 10,24,54,118,252,530,1102,2272,4654,9486,19260,38986,78726,158672,

%T 319318,641830,1288828,2586018,5185566,10393024,20821470,41700254,

%U 83493244,167136538,334515862,669424560,1339484742,2679997942,5361659964

%N Number of (1+1) X (n+1) 0..1 arrays with nondecreasing min(x(i,j),x(i,j-1)) in the i direction and nondecreasing absolute value of x(i,j)-x(i-1,j) in the j direction.

%H R. H. Hardin, <a href="/A250798/b250798.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 3*a(n-1) - a(n-2) - 2*a(n-3).

%F Empirical g.f.: 2*x*(5 - 3*x - 4*x^2) / ((1 - 2*x)*(1 - x - x^2)). - _Colin Barker_, Nov 20 2018

%e Some solutions for n=4:

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

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

%Y Row 1 of A250797.

%K nonn

%O 1,1

%A _R. H. Hardin_, Nov 27 2014

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Last modified November 29 10:00 EST 2021. Contains 349416 sequences. (Running on oeis4.)