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

Author

R. H. Hardin Dec 05 2011

Keywords

• nonn

Comments

Column 7 of A201811

Examples

			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
		

Links

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