A211582 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 three, four, six or seven distinct values for every i,j,k<=n.

16, 44, 116, 284, 696, 1672, 3996, 9580, 22656, 54456, 128292, 309676, 729304, 1768840, 4171516, 10165276, 24024384, 58797992, 139284836, 342197820, 812420344, 2002527128, 4763655900, 11774209164, 28056237376, 69503351704

Offset

1,1

Links

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

Formula

Empirical: a(n) = 2*a(n-1) + 13*a(n-2) - 26*a(n-3) - 57*a(n-4) + 116*a(n-5) + 97*a(n-6) - 216*a(n-7) - 36*a(n-8) + 144*a(n-9) - 36*a(n-10).

Empirical g.f.: 4*x*(4 + 3*x - 45*x^2 - 26*x^3 + 169*x^4 + 64*x^5 - 264*x^6 - 33*x^7 + 144*x^8 - 36*x^9) / ((1 - x)*(1 - 2*x^2)*(1 - 3*x^2)*(1 - 6*x^2)*(1 - x - 3*x^2 + x^3)). - Colin Barker, Jul 19 2018

Example

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

Crossrefs

Sequence in context: A293858 A258547 A211573 * A204032 A192143 A221593

Adjacent sequences: A211579 A211580 A211581 * A211583 A211584 A211585

Keyword

nonn

Author

R. H. Hardin, Apr 16 2012

Status

approved