A211583 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 two, three, four, six or seven distinct values for every i,j,k<=n

24, 80, 222, 560, 1392, 3346, 8024, 19004, 44796, 105568, 246694, 581026, 1352628, 3191480, 7423406, 17570428, 40904298, 97193124, 226680746, 540902924, 1264446486, 3030265486, 7101406744, 17090819062, 40152342862, 97024689184

Offset

1,1

Links

R. H. Hardin, Table of n, a(n) for n = 1..54

Formula

Empirical: a(n) = 8*a(n-1) -2*a(n-2) -139*a(n-3) +273*a(n-4) +920*a(n-5) -2924*a(n-6) -2707*a(n-7) +15107*a(n-8) +1449*a(n-9) -46166*a(n-10) +13980*a(n-11) +89658*a(n-12) -46197*a(n-13) -113421*a(n-14) +70124*a(n-15) +92999*a(n-16) -59452*a(n-17) -47547*a(n-18) +28134*a(n-19) +13644*a(n-20) -6768*a(n-21) -1620*a(n-22) +648*a(n-23)

Example

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

Crossrefs

Sequence in context: A060673 A167561 A211575 * A211589 A211597 A318988

Adjacent sequences: A211580 A211581 A211582 * A211584 A211585 A211586

Keyword

nonn

Author

R. H. Hardin Apr 16 2012

Status

approved