A188175 Number of strictly increasing arrangements of n numbers in -(n+1)..(n+1) with sum zero.

1, 3, 8, 24, 73, 227, 734, 2430, 8150, 27718, 95514, 332578, 1168261, 4136477, 14749992, 52925886, 190973410, 692583902, 2523265494, 9231352260, 33901898722, 124940568222, 461938289518, 1713007181342, 6369928427268, 23747917426918

Offset: 1

Author

R. H. Hardin Mar 23 2011

Keywords

• nonn

Comments

Column 3 of A188181.

Apparently a(n) = A046919(n+3) for 1 <= n <= 30. - Georg Fischer, Oct 24 2018

Examples

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

Links

• R. H. Hardin, Table of n, a(n) for n = 1..30

Crossrefs

Cf. A046919.