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%I #8 Nov 26 2018 16:16:05
%S 40,180,816,3728,17152,79424,369920,1731840,8144896,38458368,
%T 182218752,865931264,4125491200,19697254400,94217240576,451363012608,
%U 2165141143552,10397297147904,49974875258880,240389177999360,1157058166521856
%N Number of (n+1) X (1+1) 0..2 arrays with every 2 X 2 subblock summing to a nonzero multiple of 2.
%H R. H. Hardin, <a href="/A251203/b251203.txt">Table of n, a(n) for n = 1..210</a>
%F Empirical: a(n) = 8*a(n-1) - 12*a(n-2) - 16*a(n-3).
%F Empirical g.f.: 4*x*(10 - 35*x - 36*x^2) / ((1 - 4*x)*(1 - 4*x - 4*x^2)). - _Colin Barker_, Nov 26 2018
%e Some solutions for n=4:
%e ..2..1....1..1....2..0....0..1....0..1....2..2....2..0....0..0....2..2....2..1
%e ..1..0....1..1....0..2....1..0....0..1....1..1....0..0....2..2....2..2....1..0
%e ..1..2....0..2....2..2....1..0....2..1....1..1....2..2....2..0....2..2....1..0
%e ..1..0....1..1....2..2....1..0....2..1....1..1....0..2....2..0....2..2....2..1
%e ..2..1....0..2....2..2....0..1....1..0....2..0....2..2....2..2....1..1....1..2
%Y Column 1 of A251210.
%K nonn
%O 1,1
%A _R. H. Hardin_, Nov 30 2014
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