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%I #6 Apr 17 2022 22:49:05
%S 49,143,357,879,2053,4805,10971,25233,57391,131643,300783,692847,
%T 1595765,3701759,8601369,20105533,47103881,110883033,261621763,
%U 619556193,1470188991,3498411151,8338717447,19916838255,47634215409,114096061487
%N Number of -3..3 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="/A211501/b211501.txt">Table of n, a(n) for n = 1..210</a>
%F Empirical: a(n) = 6*a(n-1) +6*a(n-2) -97*a(n-3) +62*a(n-4) +668*a(n-5) -852*a(n-6) -2556*a(n-7) +4359*a(n-8) +5935*a(n-9) -12593*a(n-10) -8545*a(n-11) +22727*a(n-12) +7400*a(n-13) -26431*a(n-14) -3396*a(n-15) +19783*a(n-16) +389*a(n-17) -9298*a(n-18) +302*a(n-19) +2606*a(n-20) -118*a(n-21) -392*a(n-22) +12*a(n-23) +24*a(n-24).
%e Some solutions for n=5
%e ..1....0...-2....0....0....1....0....0....1...-2....1....0....0....3....3....0
%e .-1...-2...-1....2....2....3...-1...-1...-1...-2...-1....0....1....1....0...-1
%e ..3....1....0....0...-2....1...-2....0...-1...-2....0....1....2...-1....0....1
%e .-1...-2....1...-2....0...-1...-1....0....1...-2....1...-1....1....1...-3....0
%e ..0....0....0....2...-2...-3...-2....0...-1...-2....0....1....2...-1....0....1
%e .-1...-2...-1...-2....0...-1...-3....0...-1....2....0....0....3...-1....0....0
%K nonn
%O 1,1
%A _R. H. Hardin_, Apr 13 2012
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