A211572 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 one, two, three, four or five distinct values for every i,j,k<=n

25, 69, 177, 427, 1009, 2339, 5381, 12315, 28147, 64367, 147473, 338895, 781407, 1808731, 4202661, 9803439, 22952115, 53927029, 127112163, 300515927, 712369279, 1692743195, 4030861381, 9616634755, 22980554099, 54994897249, 131772223081

Offset

1,1

Links

R. H. Hardin, Table of n, a(n) for n = 1..35

Formula

Empirical: a(n) = 8*a(n-1) -14*a(n-2) -46*a(n-3) +172*a(n-4) +6*a(n-5) -626*a(n-6) +470*a(n-7) +1009*a(n-8) -1253*a(n-9) -709*a(n-10) +1354*a(n-11) +140*a(n-12) -663*a(n-13) +23*a(n-14) +148*a(n-15) -6*a(n-16) -12*a(n-17)

Example

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

Crossrefs

Sequence in context: A137186 A109676 A223888 * A087239 A032653 A063308

Adjacent sequences: A211569 A211570 A211571 * A211573 A211574 A211575

Keyword

nonn

Author

R. H. Hardin Apr 16 2012

Status

approved