A188230 Number of nondecreasing arrangements of n numbers in -(n+1)..(n+1) with sum zero and not more than two numbers equal

1, 4, 12, 52, 221, 1019, 4818, 23522, 117209, 594789, 3062414, 15966168, 84132345, 447457816, 2399177028, 12956403904, 70416558196, 384897011042, 2114694606220, 11672750655842, 64705139473661, 360068911514032, 2010827078176568

Offset

1,2

Comments

Column 3 of A188236

Links

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

Example

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

Crossrefs

Sequence in context: A259274 A109499 A282587 * A124006 A215524 A034716

Adjacent sequences: A188227 A188228 A188229 * A188231 A188232 A188233

Keyword

nonn

Author

R. H. Hardin Mar 24 2011

Status

approved