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%I #8 Jun 06 2018 09:05:31
%S 9216,186624,3779136,78428736,1631513664,34026967296,710001723456,
%T 14819050600704,309323110957056,6456825742349376,134781435261831744,
%U 2813473850104420416,58729494893765642496,1225941854009002910784
%N Number of (n+1) X 6 0..2 arrays with column and row pair sums b(i,j)=a(i,j)+a(i,j-1) and c(i,j)=a(i,j)+a(i-1,j) such that b(i,j)*b(i-1,j)-c(i,j)*c(i,j-1) is nonzero.
%C Also 0..2 arrays with no 2 X 2 subblock having equal diagonal elements or equal antidiagonal elements.
%H R. H. Hardin, <a href="/A204103/b204103.txt">Table of n, a(n) for n = 1..210</a>
%F Empirical: a(n) = 25*a(n-1) -45*a(n-2) -963*a(n-3) +2025*a(n-4) +3645*a(n-5) -6561*a(n-6).
%F Empirical g.f.: 576*x*(16 - 76*x - 819*x^2 + 2124*x^3 + 3321*x^4 - 6561*x^5) / ((1 - 25*x + 90*x^2 - 81*x^3)*(1 - 45*x^2 - 81*x^3)). - _Colin Barker_, Jun 06 2018
%e Some solutions for n=5:
%e ..2..1..1..1..0..1....0..0..2..1..0..2....2..2..1..2..2..1....1..1..2..2..2..1
%e ..0..0..2..2..2..1....1..1..2..1..0..1....0..0..1..0..0..0....2..0..0..1..0..0
%e ..2..1..1..0..0..0....0..0..2..1..0..2....1..2..2..2..1..2....1..1..2..1..2..2
%e ..2..0..2..2..1..1....1..1..2..1..0..2....1..0..1..0..0..2....2..0..2..0..0..0
%e ..1..1..1..0..0..0....2..0..2..1..0..2....2..2..1..2..1..2....1..0..2..1..2..1
%e ..2..2..2..2..1..1....1..0..2..1..0..1....0..0..0..0..0..2....1..0..2..1..2..0
%K nonn
%O 1,1
%A _R. H. Hardin_, Jan 10 2012
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