A188117 Number of strictly increasing arrangements of n nonzero numbers in -(n+2)..(n+2) with sum zero

0, 4, 8, 31, 90, 308, 1032, 3528, 12124, 42262, 148518, 525869, 1874648, 6725266, 24260940, 87958188, 320349712, 1171609968, 4301272078, 15846418258, 58569008756, 217121189648, 807123533172, 3008133255026, 11238226082080

Offset

1,2

Comments

Column 4 of A188122

Links

R. H. Hardin, Table of n, a(n) for n = 1..29

Example

Some solutions for n=6
.-4...-7...-8...-6...-7...-8...-7...-8...-8...-5...-6...-5...-7...-8...-8...-3
.-3...-5...-6...-5...-3...-5...-5...-5...-6...-4...-4...-3...-6...-2...-7...-2
.-1...-1...-4...-3...-2...-3...-3...-3...-2...-1...-2...-2....1...-1....1...-1
..1....1....5....1...-1....3....4....2....2....1....1....1....3....1....2....1
..2....4....6....6....5....6....5....6....6....2....3....2....4....4....4....2
..5....8....7....7....8....7....6....8....8....7....8....7....5....6....8....3

Crossrefs

Sequence in context: A080072 A149091 A149092 * A094502 A162459 A129195

Adjacent sequences: A188114 A188115 A188116 * A188118 A188119 A188120

Keyword

nonn

Author

R. H. Hardin Mar 21 2011

Status

approved