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%I #7 Oct 09 2015 04:20:55
%S 2120,12296,95008,839872,7919128,76028256,732727336,7068433736,
%T 68201154272,658081945168,6349980210408,61272516345744,
%U 591233822472776,5704963557044152,55048626862970856,531178036521593464
%N Number of 3X(n+1) 0..3 arrays with every 2 X 2 subblock having the same number of clockwise edge increases as its horizontal neighbors and no 2 X 2 subblock having the same number of counterclockwise edge increases as its vertical neighbors.
%C Row 2 of A205659.
%H R. H. Hardin, <a href="/A205660/b205660.txt">Table of n, a(n) for n = 1..210</a>
%F Empirical: a(n) = 12*a(n-1) -7*a(n-2) -173*a(n-3) +94*a(n-4) +1137*a(n-5) +190*a(n-6) -3906*a(n-7) -4350*a(n-8) +5407*a(n-9) +16999*a(n-10) +5544*a(n-11) -28150*a(n-12) -28396*a(n-13) +18360*a(n-14) +34596*a(n-15) -399*a(n-16) -17679*a(n-17) -2832*a(n-18) +5324*a(n-19) +1556*a(n-20) -636*a(n-21) -240*a(n-22) for n>26.
%e Some solutions for n=4:
%e ..2..0..0..1..0....1..3..0..1..1....1..2..0..1..3....3..1..3..3..3
%e ..3..2..1..3..1....0..1..2..0..2....1..3..2..0..2....1..1..1..1..1
%e ..2..2..3..3..1....3..3..2..1..3....2..2..2..2..2....1..1..1..1..1
%K nonn
%O 1,1
%A _R. H. Hardin_, Jan 30 2012
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