A211464 Number of -2..2 arrays x(i) of n+1 elements i=1..n+1 with x(i)+x(j), x(i+1)+x(j+1), -(x(i)+x(j+1)), and -(x(i+1)+x(j)) having one, three or four distinct values for every i<=n and j<=n

21, 89, 353, 1373, 5225, 19645, 73105, 270125, 992545, 3631741, 13245457, 48187085, 174966209, 634348221, 2297224145, 8311862669, 30054358337, 108618731197, 392419038993, 1417394738125, 5118764739265, 18484320138301, 66746754619345

Offset

1,1

Links

R. H. Hardin, Table of n, a(n) for n = 1..210

Formula

Empirical: a(n) = 10*a(n-1) -16*a(n-2) -118*a(n-3) +321*a(n-4) +560*a(n-5) -1724*a(n-6) -1636*a(n-7) +3492*a(n-8) +2984*a(n-9) -1216*a(n-10) -608*a(n-11) +192*a(n-12)

Example

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

Crossrefs

Sequence in context: A158540 A304514 A219886 * A268257 A223370 A223363

Adjacent sequences: A211461 A211462 A211463 * A211465 A211466 A211467

Keyword

nonn

Author

R. H. Hardin Apr 12 2012

Status

approved