A211590 - OEIS

%I #4 Apr 16 2012 07:03:08

%S 16,48,124,306,712,1682,3824,9010,20556,48942,112920,272310,635488,

%T 1549486,3649084,8971242,21265496,52582858,125191648,310754154,

%U 741987532,1846432766,4416892952,11009384758,26366956992,65790531678,157684077564

%N Number of -2..2 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 four, five, six or eight distinct values for every i,j,k<=n

%H R. H. Hardin, <a href="/A211590/b211590.txt">Table of n, a(n) for n = 1..58</a>

%F Empirical: a(n) = 4*a(n-1) +11*a(n-2) -61*a(n-3) -20*a(n-4) +343*a(n-5) -156*a(n-6) -890*a(n-7) +756*a(n-8) +1066*a(n-9) -1196*a(n-10) -504*a(n-11) +720*a(n-12) +72*a(n-13) -144*a(n-14)

%e Some solutions for n=5

%e .-1...-1...-1....2...-2...-1....1....2...-1....1...-1...-1....1...-2...-1....1

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

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

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

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

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

%K nonn

%O 1,1

%A _R. H. Hardin_ Apr 16 2012