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%I #4 Apr 18 2012 05:39:56
%S 81,233,579,1373,3147,7161,16061,36193,81085,183171,413329,940933,
%T 2145151,4930245,11361373,26362361,61352875,143585559,336993507,
%U 794383691,1877216725,4450883361,10574607261,25186420645,60085979449
%N Number of -4..4 arrays x(i) of n+1 elements i=1..n+1 with x(i)+x(j), x(i+1)+x(j+1), -(x(i)+x(j+1)), and -(x(i+1)+x(j)) having one, two or three distinct values for every i<=n and j<=n
%H R. H. Hardin, <a href="/A211690/b211690.txt">Table of n, a(n) for n = 1..210</a>
%F Empirical: a(n) = 6*a(n-1) +11*a(n-2) -127*a(n-3) +27*a(n-4) +1183*a(n-5) -1132*a(n-6) -6381*a(n-7) +8929*a(n-8) +22055*a(n-9) -38648*a(n-10) -51000*a(n-11) +107487*a(n-12) +79800*a(n-13) -203031*a(n-14) -83121*a(n-15) +265573*a(n-16) +54369*a(n-17) -240368*a(n-18) -18623*a(n-19) +148011*a(n-20) +317*a(n-21) -59912*a(n-22) +2112*a(n-23) +15014*a(n-24) -650*a(n-25) -2080*a(n-26) +60*a(n-27) +120*a(n-28)
%e Some solutions for n=5
%e ..1....0...-1....3....4...-1....1....0....4....2...-3....1....1....2...-1....4
%e .-1...-2....0...-1....0....1....0....0....0....1....2....0...-1...-2...-3...-4
%e ..0....2....1....0....4...-1...-2....3....0....0...-3....1....1....0...-1...-4
%e ..0...-2...-1...-1....0....1....2....0....0....1....2....0...-1....0....1...-4
%e ..2....2....0....0....4...-1...-2....0...-2....2...-3...-2....1....0...-1....4
%e ..0....0....1....2...-2....0....0...-3....0....3...-1....2...-3....2...-3....4
%K nonn
%O 1,1
%A _R. H. Hardin_ Apr 18 2012
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