A190064 Number of arrangements of n+1 nonzero numbers x(i) in -2..2 with the sum of div(x(i),x(i+1)), where div(a,b)=a/b produces the integer quotient implying a nonnegative remainder, equal to zero

2, 12, 40, 144, 550, 1896, 7584, 27328, 105348, 398760, 1538696, 5872800, 22646862, 87492676, 339055650, 1313842904, 5104724558, 19873572892, 77470783406, 302258087616, 1180840902336, 4618922848536, 18083348822516, 70852652846320

Offset

1,1

Comments

Column 2 of A190071

Links

R. H. Hardin, Table of n, a(n) for n = 1..200

Example

Some solutions for n=4
.-2...-1...-1...-2...-2....1....2...-1...-1....2...-2....1....2....2....1....1
.-2....1....1...-1...-1...-1....1....1...-2...-1....1....1...-1....2...-2....1
..2....1...-2....1....1...-1....2....2....1...-2....1....2....2....2....1....1
.-2...-1....2....2...-2....2...-2...-2....1....2....1...-1....1...-2....2...-1
.-2...-2....1...-2....2....2....2...-1....2....1....2...-1....1....2....1....1

Crossrefs

Sequence in context: A013194 A212874 A074447 * A240122 A110953 A003683

Adjacent sequences: A190061 A190062 A190063 * A190065 A190066 A190067

Keyword

nonn

Author

R. H. Hardin May 04 2011

Status

approved