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%I #4 Apr 18 2012 05:38:27
%S 69,173,375,765,1545,3029,5973,11621,22759,44341,86833,169841,333421,
%T 654917,1289687,2542733,5021945,9931349,19663237,38977973,77326087,
%U 153558325,305104801,606719185,1206917981,2402499477,4783531511
%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 or three distinct values for every i<=n and j<=n
%H R. H. Hardin, <a href="/A211688/b211688.txt">Table of n, a(n) for n = 1..210</a>
%F Empirical: a(n) = 3*a(n-1) +10*a(n-2) -35*a(n-3) -35*a(n-4) +160*a(n-5) +45*a(n-6) -365*a(n-7) +6*a(n-8) +437*a(n-9) -55*a(n-10) -260*a(n-11) +30*a(n-12) +60*a(n-13)
%e Some solutions for n=5
%e .-2...-4....4....1....2....2....0....0....2...-4....1....0....3....0....0....0
%e ..2....0....2....2....0....0....3....0....0...-3....0....4....2....2...-1...-3
%e ..0....4....4....1....0....0....0....4....2...-2....1...-4....1...-2....1....0
%e .-2....0....2....2....2....0....0....0...-2...-1....2....4....2....0....0....0
%e ..2....0....0....3....0...-4....0....0....0....0....3....0....1...-2....1...-3
%e .-2....4....2....4...-1....0....0...-4....2...-1....4....4....0....0...-1....0
%K nonn
%O 1,1
%A _R. H. Hardin_ Apr 18 2012
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