A188176 Number of strictly increasing arrangements of n numbers in -(n+2)..(n+2) with sum zero

1, 4, 13, 43, 141, 480, 1656, 5744, 20094, 70922, 252117, 901723, 3243531, 11728606, 42611990, 155484150, 569585274, 2094177794, 7725489976, 28588154238, 106095329440, 394792407478, 1472734812454, 5506709078310, 20635115495666

Offset

1,2

Comments

Column 4 of A188181

Links

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

Example

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

Crossrefs

Sequence in context: A266494 A121486 A339063 * A003688 A033434 A297928

Adjacent sequences: A188173 A188174 A188175 * A188177 A188178 A188179

Keyword

nonn

Author

R. H. Hardin Mar 23 2011

Status

approved