A188228 Number of nondecreasing arrangements of n numbers in -(n-1)..(n-1) with sum zero and not more than two numbers equal

1, 2, 4, 15, 58, 245, 1082, 5020, 24040, 118154, 592332, 3019280, 15604848, 81614541, 431227650, 2298833499, 12350952158, 66818754504, 363727676848, 1990946917066, 10952512200610, 60525264890259, 335856363303010, 1870732844007387

Offset

1,2

Comments

Column 1 of A188236

Links

R. H. Hardin, Table of n, a(n) for n = 1..31

Example

All solutions for n=4
.-3...-1...-2...-3...-3...-2...-1...-2...-3...-2...-3...-1...-2...-2...-3
.-1...-1....0....0...-2...-2...-1...-2...-3....0....0....0...-1...-1...-1
..1....0....1....1....2....1....1....2....3....0....0....0....0....1....2
..3....2....1....2....3....3....1....2....3....2....3....1....3....2....2

Crossrefs

Sequence in context: A316726 A308345 A280065 * A243796 A153939 A112281

Adjacent sequences: A188225 A188226 A188227 * A188229 A188230 A188231

Keyword

nonn

Author

R. H. Hardin Mar 24 2011

Status

approved