A211584 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 seven distinct values for every i,j,k<=n.

16, 48, 128, 302, 704, 1622, 3696, 8626, 19784, 47062, 109280, 264218, 620192, 1517126, 3588888, 8847682, 21038192, 52125406, 124356752, 309096434, 738979400, 1840516550, 4406202720, 10988503498, 26329344800, 65717431510, 157552717784

Offset

1,1

Links

R. H. Hardin, Table of n, a(n) for n = 1..37

Formula

Empirical: a(n) = 3*a(n-1) + 10*a(n-2) - 35*a(n-3) - 25*a(n-4) + 130*a(n-5) - 180*a(n-7) + 36*a(n-8) + 72*a(n-9).

Empirical g.f.: 2*x*(8 - 88*x^2 - x^3 + 299*x^4 + 45*x^5 - 340*x^6 - 126*x^7 + 60*x^8) / ((1 - 2*x)*(1 - x - x^2)*(1 - 2*x^2)*(1 - 3*x^2)*(1 - 6*x^2)). - Colin Barker, Jul 19 2018

Example

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

Crossrefs

Sequence in context: A190112 A211576 A211590 * A211598 A235541 A109098

Adjacent sequences: A211581 A211582 A211583 * A211585 A211586 A211587

Keyword

nonn

Author

R. H. Hardin, Apr 16 2012

Status

approved