A211589 - OEIS

%I #4 Apr 16 2012 07:02:19

%S 24,80,226,596,1536,3966,10192,26572,69102,182368,479844,1278318,

%T 3393724,9100172,24316814,65498292,175852800,475172186,1280321244,

%U 3467619648,9369009790,25419829164,68829542860,187003542158,507226552512

%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 two, three, four, six or eight distinct values for every i,j,k<=n

%H R. H. Hardin, <a href="/A211589/b211589.txt">Table of n, a(n) for n = 1..35</a>

%F Empirical: a(n) = 7*a(n-1) -6*a(n-2) -60*a(n-3) +139*a(n-4) +94*a(n-5) -507*a(n-6) +148*a(n-7) +690*a(n-8) -428*a(n-9) -372*a(n-10) +272*a(n-11) +72*a(n-12) -48*a(n-13)

%e Some solutions for n=5

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

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

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

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

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

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

%K nonn

%O 1,1

%A _R. H. Hardin_ Apr 16 2012