A189957 1/4 the number of arrangements of 8 nonzero numbers x(i) in -n..n with the sum of sign(x(i))*(|x(i)| mod x(i+1)) equal to zero

64, 4632, 72744, 542353, 2514945, 9133420, 26586582, 68081570, 154928607, 325585559, 631690148, 1167609345, 2043508680, 3435508142, 5566095860, 8767568010, 13387924849, 20010820026, 29195103851, 41845814529, 58906853906

Offset

1,1

Comments

Row 7 of A189951

Links

R. H. Hardin, Table of n, a(n) for n = 1..61

Example

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

Crossrefs

Sequence in context: A099369 A249393 A208708 * A146496 A058874 A302264

Adjacent sequences: A189954 A189955 A189956 * A189958 A189959 A189960

Keyword

nonn

Author

R. H. Hardin May 02 2011

Status

approved