A211722 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 two, three or four distinct values for every i,j,k<=n.

48, 82, 140, 250, 448, 824, 1520, 2852, 5364, 10208, 19464, 37428, 72080, 139688, 271012, 528328, 1030776, 2018668, 3955520, 7774312, 15285508, 30128648, 59399624, 117351116, 231876816, 458968664, 908552868, 1801178616, 3570988568

Offset

1,1

Links

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

Formula

Empirical: a(n) = 4*a(n-1) + 2*a(n-2) - 25*a(n-3) + 16*a(n-4) + 46*a(n-5) - 48*a(n-6) - 26*a(n-7) + 36*a(n-8) + 4*a(n-9) - 8*a(n-10).

Empirical g.f.: 2*x*(24 - 55*x - 142*x^2 + 363*x^3 + 225*x^4 - 744*x^5 - 65*x^6 + 534*x^7 - 14*x^8 - 124*x^9) / ((1 - x)*(1 - 2*x)*(1 - x - x^2)*(1 - 2*x^2)*(1 - 4*x^2 + 2*x^4)). - Colin Barker, Jul 20 2018

Example

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

Crossrefs

Sequence in context: A065911 A260841 A260767 * A260834 A260760 A260501

Adjacent sequences: A211719 A211720 A211721 * A211723 A211724 A211725

Keyword

nonn

Author

R. H. Hardin, Apr 20 2012

Status

approved