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%I #5 Mar 31 2012 12:37:30
%S 576,12492,266126,5719838,122871278,2641341716,56780957220,
%T 1220714555712,26243950399348,564220215862026,12130228710486118,
%U 260789425643620742,5606749493903244274,120540344808285189504,2591515087636992673274
%N Half the number of (n+1)X3 0..3 arrays with every 2X2 subblock having exactly one duplicate clockwise edge difference
%C Column 2 of A209787
%H R. H. Hardin, <a href="/A209781/b209781.txt">Table of n, a(n) for n = 1..210</a>
%F Empirical: a(n) = 32*a(n-1) -181*a(n-2) -1612*a(n-3) +14245*a(n-4) +3934*a(n-5) -228072*a(n-6) +286957*a(n-7) +1135539*a(n-8) -2087315*a(n-9) -2118396*a(n-10) +5249880*a(n-11) +1194011*a(n-12) -5705343*a(n-13) +530140*a(n-14) +2648017*a(n-15) -619565*a(n-16) -439672*a(n-17) +116050*a(n-18) +17928*a(n-19) -3952*a(n-20)
%e Some solutions for n=4
%e ..1..1..2....2..2..0....0..1..0....1..0..0....0..3..0....2..0..2....1..1..3
%e ..0..2..2....2..0..0....2..1..2....0..0..3....0..3..3....2..1..1....2..1..1
%e ..1..1..3....0..0..1....1..1..0....1..2..1....2..1..1....3..3..2....1..1..3
%e ..2..2..2....2..2..1....3..1..1....0..2..3....0..1..0....0..3..3....2..3..3
%e ..2..1..1....0..0..3....0..2..3....1..1..3....2..2..2....3..3..1....1..3..1
%K nonn
%O 1,1
%A _R. H. Hardin_ Mar 13 2012