A211583 - OEIS

%I #4 Apr 16 2012 06:57:17

%S 24,80,222,560,1392,3346,8024,19004,44796,105568,246694,581026,

%T 1352628,3191480,7423406,17570428,40904298,97193124,226680746,

%U 540902924,1264446486,3030265486,7101406744,17090819062,40152342862,97024689184

%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 seven distinct values for every i,j,k<=n

%H R. H. Hardin, <a href="/A211583/b211583.txt">Table of n, a(n) for n = 1..54</a>

%F Empirical: a(n) = 8*a(n-1) -2*a(n-2) -139*a(n-3) +273*a(n-4) +920*a(n-5) -2924*a(n-6) -2707*a(n-7) +15107*a(n-8) +1449*a(n-9) -46166*a(n-10) +13980*a(n-11) +89658*a(n-12) -46197*a(n-13) -113421*a(n-14) +70124*a(n-15) +92999*a(n-16) -59452*a(n-17) -47547*a(n-18) +28134*a(n-19) +13644*a(n-20) -6768*a(n-21) -1620*a(n-22) +648*a(n-23)

%e Some solutions for n=5

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

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

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

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

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

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

%K nonn

%O 1,1

%A _R. H. Hardin_ Apr 16 2012