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%I #7 Jan 09 2019 09:12:40
%S 2,2,6,14,22,46,102,190,374,782,1542,3038,6166,12334,24486,49150,
%T 98486,196430,393030,786974,1572694,3144814,6292710,12583486,25162742,
%U 50333582,100667526,201318494,402652822,805322926,1610596902,3221208190
%N Number of n X 3 integer arrays with each element equal to the number of horizontal and antidiagonal neighbors equal to itself.
%H R. H. Hardin, <a href="/A266007/b266007.txt">Table of n, a(n) for n = 1..210</a>
%F Empirical: a(n) = a(n-1) + 4*a(n-3).
%F Empirical g.f.: 2*x*(1 + 2*x^2) / ((1 - 2*x)*(1 + x + 2*x^2)). - _Colin Barker_, Jan 09 2019
%e Some solutions for n=4:
%e ..1..1..0....0..1..0....1..1..0....1..1..0....0..1..1....0..2..2....0..1..0
%e ..0..2..2....1..2..2....0..1..0....0..2..2....0..2..2....2..2..1....1..2..2
%e ..2..2..1....2..2..0....1..2..2....2..2..0....2..2..1....0..1..0....2..2..0
%e ..0..1..0....1..1..0....2..2..0....1..1..0....0..1..0....0..1..1....0..1..1
%Y Column 3 of A266012.
%K nonn
%O 1,1
%A _R. H. Hardin_, Dec 20 2015
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