A189538 Number of arrangements of n+1 nonzero numbers x(i) in -2..2 with the sum of trunc(x(i)/x(i+1)) equal to zero

4, 8, 44, 152, 552, 2000, 7628, 28440, 108792, 411888, 1586424, 6066032, 23474384, 90378912, 351072012, 1358520600, 5293045208, 20561697200, 80309986856, 312934745552, 1224770426672, 4784290151264, 18757260263352, 73421632108656

Offset

1,1

Comments

Column 2 of A189545

Links

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

Example

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

Crossrefs

Sequence in context: A045639 A337782 A285751 * A351071 A270352 A183394

Adjacent sequences: A189535 A189536 A189537 * A189539 A189540 A189541

Keyword

nonn

Author

R. H. Hardin Apr 23 2011

Status

approved