A211766 - OEIS

%I #9 Jul 20 2018 06:02:47

%S 48,330,2264,15512,106128,725040,4946132,33693740,229205328,

%T 1557067320,10563664724,71575622300,484371525216,3273973248600,

%U 22104207166532,149072726510492,1004302970917488,6759180631475928,45446982868078004

%N Number of -3..3 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 two, three, four, five, six, seven or eight distinct values for every i,j,k<=n.

%H R. H. Hardin, <a href="/A211766/b211766.txt">Table of n, a(n) for n = 1..44</a>

%F Empirical: a(n) = 24*a(n-1) - 206*a(n-2) + 684*a(n-3) - 251*a(n-4) - 1740*a(n-5) - 1210*a(n-6) - 300*a(n-7) - 24*a(n-8).

%F Empirical g.f.: 2*x*(24 - 411*x + 2116*x^2 - 1838*x^3 - 6724*x^4 - 4393*x^5 - 1062*x^6 - 84*x^7) / ((1 - 6*x - x^2)*(1 - 6*x - 2*x^2)*(1 - 6*x - 3*x^2)*(1 - 6*x - 4*x^2)). - _Colin Barker_, Jul 20 2018

%e Some solutions for n=5:

%e ..1...-1....3....1...-1...-1...-1....2...-3...-2...-3....2...-1....2....3....0

%e ..1....3...-1....0....1...-1...-3....0...-2....1....3....3...-3...-3...-3...-3

%e .-1...-3...-1...-3....0....1....1....3....2...-1...-2...-3....1...-3....0....0

%e ..1...-1...-2....1...-3....2....1...-3...-3...-1...-2...-3....2....0....2....1

%e .-3...-1...-2...-2....2....3...-2....0....1....1...-1....3...-2....2....3....0

%e ..1...-2....1....2....3....2....3....1....1...-1...-2...-1...-2...-3....0...-1

%K nonn

%O 1,1

%A _R. H. Hardin_, Apr 20 2012