A189945 1/4 the number of arrangements of n+1 nonzero numbers x(i) in -3..3 with the sum of sign(x(i))*(|x(i)| mod x(i+1)) equal to zero

5, 15, 63, 384, 2393, 13569, 72744, 393006, 2206620, 12731028, 73789033, 425385252, 2445427072, 14098065430, 81698759400, 475327637850, 2770724256604, 16165039535028, 94402460826924, 552050600817600, 3233027830180059

Offset

1,1

Comments

Column 3 of A189951

Links

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

Example

Some solutions with n=4
.-3....3....1...-1....3....3...-1....1....3...-3...-3....1....2....2....3...-3
.-1...-2....2...-2....2....2...-3...-3...-3....3....1....3...-3...-1...-3...-2
..3....3...-3....2...-1...-1....1...-2....1....3...-2...-3...-2....1....1....1
..1....2...-2....1...-2...-1....1....2....1....3....3...-2...-1....1...-3....2
.-2...-2...-3...-3....1...-3....3...-2....1...-3....2....1....3....1....2....1

Crossrefs

Sequence in context: A149614 A149615 A149616 * A066886 A149617 A149618

Adjacent sequences: A189942 A189943 A189944 * A189946 A189947 A189948

Keyword

nonn

Author

R. H. Hardin May 02 2011

Status

approved