A211723 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, four or five distinct values for every i,j,k<=n.

48, 94, 162, 294, 508, 922, 1640, 3032, 5562, 10484, 19708, 37718, 72128, 139540, 269914, 526084, 1025412, 2009038, 3936456, 7741548, 15225514, 30027724, 59222348, 117056558, 231372240, 458136788, 907150906, 1798879268, 3567156212

Offset

1,1

Links

R. H. Hardin, Table of n, a(n) for n = 1..58

Formula

Empirical: a(n) = 4*a(n-1) + 2*a(n-2) - 25*a(n-3) + 16*a(n-4) + 46*a(n-5) - 48*a(n-6) - 26*a(n-7) + 36*a(n-8) + 4*a(n-9) - 8*a(n-10).

Empirical g.f.: 2*x*(24 - 49*x - 155*x^2 + 329*x^3 + 295*x^4 - 680*x^5 - 163*x^6 + 466*x^7 + 22*x^8 - 100*x^9) / ((1 - x)*(1 - 2*x)*(1 - x - x^2)*(1 - 2*x^2)*(1 - 4*x^2 + 2*x^4)). - Colin Barker, Jul 20 2018

Example

Some solutions for n=5:
.-2...-3....3....3....3...-3....2....2...-3...-2....2...-3...-1....3....1....0
.-2....3....0....3...-3...-3...-2....2...-3...-2....0....0...-1....1....0....1
.-2...-3...-3....3....0...-3....0....2....3....2....2....3....1....3...-1....0
.-2...-3....0....3...-3....3...-2...-1...-3....2....0....0....1....1...-2....1
.-2....3....3...-3....0...-3....0....2...-3....2....2....3....1....3...-1....0
..1....3....0...-3...-3....3...-2...-1....3....2....0....0....1...-3....0...-1

Crossrefs

Sequence in context: A260070 A260973 A260063 * A274899 A218486 A043418

Adjacent sequences: A211720 A211721 A211722 * A211724 A211725 A211726

Keyword

nonn

Author

R. H. Hardin, Apr 20 2012

Status

approved