A211739 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 three, four, six or seven distinct values for every i,j,k<=n

36, 154, 476, 1312, 3520, 9400, 25068, 68180, 185416, 516528, 1433876, 4074308, 11493872, 33137744, 94574204, 275489652, 792675160, 2325832112, 6730524532, 19849806372, 57673005088, 170710336128, 497407980332, 1476146725844

Offset

1,1

Links

R. H. Hardin, Table of n, a(n) for n = 1..50

Formula

Empirical: a(n) = 4*a(n-1) +22*a(n-2) -99*a(n-3) -180*a(n-4) +970*a(n-5) +708*a(n-6) -4972*a(n-7) -1477*a(n-8) +14770*a(n-9) +1870*a(n-10) -26181*a(n-11) -2206*a(n-12) +26960*a(n-13) +2792*a(n-14) -14620*a(n-15) -1944*a(n-16) +3328*a(n-17) +320*a(n-18) -256*a(n-19)

Example

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

Crossrefs

Sequence in context: A250632 A211728 A211737 * A211748 A211757 A250633

Adjacent sequences: A211736 A211737 A211738 * A211740 A211741 A211742

Keyword

nonn

Author

R. H. Hardin Apr 20 2012

Status

approved