A211728 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 four or six distinct values for every i,j,k<=n

36, 154, 448, 1224, 3228, 8696, 23292, 64212, 176272, 496644, 1389716, 3979200, 11286068, 32691460, 93606312, 273411380, 788182764, 2316178480, 6709685212, 19804977492, 57576268080, 170502012884, 496958379540, 1475177533296

Offset

1,1

Links

R. H. Hardin, Table of n, a(n) for n = 1..61

Formula

Empirical: a(n) = 5*a(n-1) +17*a(n-2) -118*a(n-3) -56*a(n-4) +1070*a(n-5) -496*a(n-6) -4844*a(n-7) +4493*a(n-8) +11849*a(n-9) -14605*a(n-10) -15566*a(n-11) +23460*a(n-12) +9996*a(n-13) -18780*a(n-14) -2440*a(n-15) +6592*a(n-16) +192*a(n-17) -768*a(n-18)

Example

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

Crossrefs

Sequence in context: A275496 A117511 A250632 * A211737 A211739 A211748

Adjacent sequences: A211725 A211726 A211727 * A211729 A211730 A211731

Keyword

nonn

Author

R. H. Hardin Apr 20 2012

Status

approved