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A250799 Number of (2+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.

%I A250799 #7 Nov 20 2018 10:57:45
%S A250799 24,66,162,376,838,1818,3868,8114,16842,34680,70974,144562,293356,
%T A250799 593562,1198210,2414360,4857750,9762474,19600956,39324898,78848794,
%U A250799 158019576,316560142,633963266,1269290508,2540787978,5085146898,10176071704
%N A250799 Number of (2+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 A250799 R. H. Hardin, <a href="/A250799/b250799.txt">Table of n, a(n) for n = 1..210</a>
%F A250799 Empirical: a(n) = 4*a(n-1) - 4*a(n-2) - a(n-3) + 2*a(n-4).
%F A250799 Empirical g.f.: 2*x*(12 - 15*x - 3*x^2 + 8*x^3) / ((1 - x)*(1 - 2*x)*(1 - x - x^2)). - _Colin Barker_, Nov 20 2018
%e A250799 Some solutions for n=4:
%e A250799 ..1..0..0..0..1....1..0..0..1..0....0..0..1..0..1....0..1..0..0..0
%e A250799 ..1..0..0..0..1....1..0..0..1..1....0..0..0..1..0....0..1..0..0..0
%e A250799 ..1..0..0..0..0....1..0..0..1..1....0..0..0..1..0....0..1..1..1..1
%Y A250799 Row 2 of A250797.
%K A250799 nonn
%O A250799 1,1
%A A250799 _R. H. Hardin_, Nov 27 2014