A250799 - OEIS

%I #7 Nov 20 2018 10:57:45

%S 24,66,162,376,838,1818,3868,8114,16842,34680,70974,144562,293356,

%T 593562,1198210,2414360,4857750,9762474,19600956,39324898,78848794,

%U 158019576,316560142,633963266,1269290508,2540787978,5085146898,10176071704

%N 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 R. H. Hardin, <a href="/A250799/b250799.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 4*a(n-1) - 4*a(n-2) - a(n-3) + 2*a(n-4).

%F 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 Some solutions for n=4:

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

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

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

%Y Row 2 of A250797.

%K nonn

%O 1,1

%A _R. H. Hardin_, Nov 27 2014