A201806 Number of arrays of n integers in -3..3 with sum zero and equal numbers of elements greater than zero and less than zero

1, 7, 19, 151, 631, 4621, 23857, 164599, 948871, 6359617, 38944357, 258107389, 1636264813, 10819063087, 70033892299, 463844386999, 3042796871863, 20218887555601, 133836585431269, 892623030133681, 5947033694372881

Offset

1,2

Comments

Column 3 of A201811

Links

R. H. Hardin, Table of n, a(n) for n = 1..210

Example

Some solutions for n=7
.-3....2....0...-1...-3....3....1....3...-1....3....0...-2....1...-3....0...-3
.-3....3...-2...-1....1....1...-1....2...-3....3....1....3....3...-2....0....3
.-3....0....3...-2...-1....0...-2...-2....1....1...-2...-3....0....1....2....0
..3...-3...-2....2...-1...-1....3...-2....2...-2....2....3....2....0...-3....0
..3....2....3....1....3....1....0....0....0...-2...-2....2...-1....3...-2....0
..3...-3....1....0....1...-1....1....2...-1...-3....3...-3...-3....2....0...-3
..0...-1...-3....1....0...-3...-2...-3....2....0...-2....0...-2...-1....3....3

Crossrefs

Sequence in context: A267276 A328713 A096321 * A346943 A128338 A173384

Adjacent sequences: A201803 A201804 A201805 * A201807 A201808 A201809

Keyword

nonn

Author

R. H. Hardin Dec 05 2011

Status

approved