A189949 1/4 the number of arrangements of n+1 nonzero numbers x(i) in -7..7 with the sum of sign(x(i))*(|x(i)| mod x(i+1)) equal to zero

16, 75, 889, 13034, 168737, 2095080, 26586582, 346371666, 4569825052, 60616719909, 807520929855, 10805101528251, 145152790595820, 1956318942197183, 26437935517478725, 358117322511949885

Offset

1,1

Comments

Column 7 of A189951

Links

R. H. Hardin, Table of n, a(n) for n = 1..96

Example

Some solutions with n=3
.-5....7....1...-6...-6....6...-1....4....1....2...-4...-3....7....1...-1...-3
.-2....6....3....6....2....1....2...-7....7...-6...-4....2...-6...-3....3....1
..1...-1...-2...-5...-6...-7...-7...-5...-2....4...-2...-4...-1...-3....1...-3
.-7...-3...-4...-2...-4...-3....6...-3...-6...-1....2...-3....3....2....5....2

Crossrefs

Sequence in context: A250353 A212690 A244835 * A103111 A118862 A118532

Adjacent sequences: A189946 A189947 A189948 * A189950 A189951 A189952

Keyword

nonn

Author

R. H. Hardin May 02 2011

Status

approved