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

1,2

Comments

Column 3 of A188181.

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

Links

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

Example

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

Crossrefs

Cf. A046919.

Sequence in context: A118264 A006365 A178543 * A046919 A291886 A275856

Adjacent sequences: A188172 A188173 A188174 * A188176 A188177 A188178

Keyword

nonn

Author

R. H. Hardin Mar 23 2011

Status

approved