A201810 Number of arrays of n integers in -7..7 with sum zero and equal numbers of elements greater than zero and less than zero

1, 15, 43, 1471, 7071, 207621, 1355145, 33222463, 266948431, 5714583505, 53305896645, 1032485634181, 10748736159253, 193347106894215, 2184638624782083, 37202261536824063, 447056372628222463

Offset

1,2

Comments

Column 7 of A201811

Links

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

Example

Some solutions for n=5
.-5....2...-3...-5...-3....2....4....1...-7....6....0....3....4....0...-2...-6
..1....3....0....5....2...-3....6...-4....0...-3....1...-4....0....7...-5....3
..0....0...-5...-4....6...-3....0....0....7....3...-2....0....6....1....3....0
.-3...-4....5....4...-5....4...-4...-4....2...-6...-1....2...-7...-1....4....5
..7...-1....3....0....0....0...-6....7...-2....0....2...-1...-3...-7....0...-2

Crossrefs

Sequence in context: A193647 A133343 A027845 * A364081 A292018 A289669

Adjacent sequences: A201807 A201808 A201809 * A201811 A201812 A201813

Keyword

nonn

Author

R. H. Hardin Dec 05 2011

Status

approved