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%I #7 Jul 18 2018 14:30:49
%S 9,27,77,199,503,1239,3021,7303,17583,42217,101245,242683,581751,
%T 1395031,3347035,8035199,19302063,46395265,111581119,268493349,
%U 646366887,1556696779,3750472401,9038662155,21789121821,52538282553,126706173657
%N Number of -1..1 arrays x(i) of n+1 elements i=1..n+1 with set{t,u,v in 0,1}((x[i+t]+x[j+u]+x[k+v])*(-1)^(t+u+v)) having one, two, three, four, five or six distinct values for every i,j,k<=n.
%H R. H. Hardin, <a href="/A211531/b211531.txt">Table of n, a(n) for n = 1..55</a>
%F Empirical: a(n) = 5*a(n-1) - 3*a(n-2) - 17*a(n-3) + 17*a(n-4) + 22*a(n-5) - 18*a(n-6) - 14*a(n-7) + 3*a(n-8) + 2*a(n-9).
%F Empirical g.f.: x*(9 - 18*x - 31*x^2 + 48*x^3 + 45*x^4 - 27*x^5 - 23*x^6 + x^7 + 2*x^8) / ((1 + x)*(1 - 2*x)*(1 - x - x^2)*(1 - 2*x - x^2)*(1 - x - 2*x^2 + x^3)). - _Colin Barker_, Jul 18 2018
%e Some solutions for n=5:
%e .-1....0...-1....1...-1....0....0....1....0....0....0....1....0....0....1....1
%e .-1....0....1...-1....0....0....1....1....0....1...-1....1....0....1...-1....0
%e ..1...-1....1...-1....1....1....1....1....0...-1....0....1....0...-1...-1....1
%e ..0....0....1...-1....0...-1....1...-1....1...-1...-1....0....1....0....1...-1
%e ..0....1....1...-1...-1....1....0...-1...-1....1....0...-1....1....0....1....1
%e ..1....0...-1....1....0...-1....0...-1....1...-1...-1....0....1...-1...-1...-1
%K nonn
%O 1,1
%A _R. H. Hardin_, Apr 14 2012
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