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A251003 Number of (n+1) X (1+1) 0..2 arrays with no 2 X 2 subblock having its maximum diagonal element less than the absolute difference of its antidiagonal elements. 1

%I

%S 69,530,4083,31456,242326,1866789,14381065,110786519,853459216,

%T 6574740657,50649420520,390184789500,3005842285913,23155920197037,

%U 178384821680265,1374212051826542,10586431881352371,81554036605596548

%N Number of (n+1) X (1+1) 0..2 arrays with no 2 X 2 subblock having its maximum diagonal element less than the absolute difference of its antidiagonal elements.

%H R. H. Hardin, <a href="/A251003/b251003.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 9*a(n-1) - 12*a(n-2) + 17*a(n-3) - 12*a(n-4) + 4*a(n-5).

%F Empirical g.f.: x*(69 - 91*x + 141*x^2 - 104*x^3 + 36*x^4) / (1 - 9*x + 12*x^2 - 17*x^3 + 12*x^4 - 4*x^5). - _Colin Barker_, Nov 24 2018

%e Some solutions for n=4:

%e ..0..0....1..2....0..0....1..0....0..0....1..1....0..2....2..1....2..0....1..0

%e ..1..2....2..2....0..2....0..0....0..1....2..2....2..0....0..2....0..2....0..1

%e ..2..0....2..2....2..1....2..2....1..2....2..1....1..0....2..0....2..1....1..0

%e ..2..1....2..0....2..1....1..2....2..2....2..1....1..1....2..0....1..2....1..1

%e ..2..2....0..0....2..0....0..2....1..2....0..1....0..0....2..2....1..2....2..1

%Y Column 1 of A251010.

%K nonn

%O 1,1

%A _R. H. Hardin_, Nov 29 2014

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Last modified August 17 00:01 EDT 2022. Contains 356180 sequences. (Running on oeis4.)