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%I #7 Dec 10 2015 02:15:55
%S 1764,9831,87918,875760,8986929,93488811,976932162,10250633343,
%T 107760730911,1134683089512,11958281270577,126112581616143,
%U 1330517219011788,14041341384337191,148208705188726647
%N Number of (n+1) X 4 0..2 arrays with every 2 X 2 subblock having the same number of clockwise edge increases as its horizontal neighbors and the same number of counterclockwise edge increases as its vertical neighbors.
%C Column 3 of A205917.
%H R. H. Hardin, <a href="/A205912/b205912.txt">Table of n, a(n) for n = 1..210</a>
%F Empirical: a(n) = 16*a(n-1) -8*a(n-2) -775*a(n-3) +2020*a(n-4) +10484*a(n-5) -34209*a(n-6) -68090*a(n-7) +249504*a(n-8) +300963*a(n-9) -1131752*a(n-10) -899412*a(n-11) +3504902*a(n-12) +1424118*a(n-13) -6769192*a(n-14) -1246800*a(n-15) +7700896*a(n-16) +2186200*a(n-17) -6370208*a(n-18) -3919560*a(n-19) +5579640*a(n-20) +2517392*a(n-21) -3579296*a(n-22) -391776*a(n-23) +1328736*a(n-24) -428352*a(n-25) +34560*a(n-26) for n>32.
%e Some solutions for n=4:
%e ..1..2..0..1....1..2..0..2....1..0..0..2....0..0..0..0....2..1..0..2
%e ..2..2..0..0....1..2..2..2....1..0..2..2....2..2..2..2....1..2..1..0
%e ..1..2..0..1....2..2..0..2....0..0..2..1....1..1..1..1....2..1..2..1
%e ..2..2..0..0....2..0..0..0....2..2..2..2....2..2..1..2....0..2..0..2
%e ..0..0..0..2....2..2..2..2....2..0..0..2....2..1..1..2....2..0..1..0
%K nonn
%O 1,1
%A _R. H. Hardin_, Feb 01 2012
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