A188231 Number of nondecreasing arrangements of n numbers in -(n+2)..(n+2) with sum zero and not more than two numbers equal

1, 5, 17, 81, 374, 1818, 8964, 45225, 231596, 1202495, 6313385, 33473871, 178991409, 964308854, 5229780968, 28531772394, 156491164870, 862470267275, 4774186037351, 26533145487533, 148001670048543, 828332995017980

Offset

1,2

Comments

Column 4 of A188236

Links

R. H. Hardin, Table of n, a(n) for n = 1..28

Example

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

Crossrefs

Sequence in context: A179605 A149751 A303713 * A023253 A149752 A149753

Adjacent sequences: A188228 A188229 A188230 * A188232 A188233 A188234

Keyword

nonn

Author

R. H. Hardin Mar 24 2011

Status

approved