A189547 Number of arrangements of 4 nonzero numbers x(i) in -n..n with the sum of trunc(x(i)/x(i+1)) equal to zero.

0, 44, 192, 544, 1340, 2520, 4620, 7716, 12500, 18896, 27876, 38860, 53492, 71460, 93972, 121328, 155180, 194484, 241980, 296528, 360804, 434048, 519528, 614164, 723528, 845504, 983924, 1136840, 1309496, 1497332, 1707736, 1938160, 2193024

Offset

1,2

Comments

Row 3 of A189545.

Links

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

Example

Some solutions for n=5
..5...-1....5....1...-4...-1...-2...-3...-1....4....3....1....4....4...-1....1
.-2....2....3....1....3....4....5....2...-1...-3....2....1....3....4...-2...-2
.-1...-2....5....5...-5....3....2....5...-3...-4...-2...-1...-2...-4....3....2
.-5...-2...-4...-4...-4...-3...-1....4....3...-3...-4...-5...-3...-5....5....2

Crossrefs

Cf. A189545.

Sequence in context: A006563 A159033 A238249 * A026908 A183246 A186248

Adjacent sequences: A189544 A189545 A189546 * A189548 A189549 A189550

Keyword

nonn

Author

R. H. Hardin Apr 23 2011

Status

approved