A211593 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, three, four, five, six or eight distinct values for every i,j,k<=n

17, 61, 189, 537, 1405, 3605, 8909, 22093, 53669, 131917, 319837, 786941, 1915309, 4734125, 11587605, 28797317, 70895933, 177097381, 438296237, 1099734997, 2734106629, 6885392301, 17183667245, 43402287421, 108663538381, 275107471725

Offset

1,1

Links

R. H. Hardin, Table of n, a(n) for n = 1..51

Formula

Empirical: a(n) = 4*a(n-1) +17*a(n-2) -81*a(n-3) -105*a(n-4) +675*a(n-5) +245*a(n-6) -3021*a(n-7) +198*a(n-8) +7895*a(n-9) -2282*a(n-10) -12190*a(n-11) +4928*a(n-12) +10646*a(n-13) -4768*a(n-14) -4680*a(n-15) +2016*a(n-16) +792*a(n-17) -288*a(n-18)

Example

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

Crossrefs

Sequence in context: A039607 A142299 A211579 * A211587 A362069 A226026

Adjacent sequences: A211590 A211591 A211592 * A211594 A211595 A211596

Keyword

nonn

Author

R. H. Hardin Apr 16 2012

Status

approved