A188240 Number of nondecreasing arrangements of 7 numbers in -(n+5)..(n+5) with sum zero and not more than two numbers equal

1082, 2395, 4818, 8964, 15696, 26123, 41748, 64370, 96346, 140463, 200176, 279520, 383424, 517461, 688344, 903624, 1172142, 1503785, 1910034, 2403502, 2998722, 3711609, 4560190, 5564140, 6745632, 8128589, 9739838, 11608268, 13765902

Offset

1,1

Comments

Row 7 of A188236

Links

R. H. Hardin, Table of n, a(n) for n = 1..200

Formula

Empirical: a(n)=2*a(n-1)-a(n-3)-a(n-5)+a(n-6)-2*a(n-7)+2*a(n-8)+a(n-9)-a(n-13)-2*a(n-14)+2*a(n-15)-a(n-16)+a(n-17)+a(n-19)-2*a(n-21)+a(n-22)

Example

Some solutions for n=4
.-6...-7...-9...-8...-7...-5...-8...-9...-4...-8...-6...-6...-6...-8...-9...-7
.-4...-5...-9...-6...-6...-5...-5...-8...-3...-7...-6...-5...-6...-8...-5...-7
.-2...-2....1...-3...-2...-1...-5...-8...-3...-3....0...-5...-3...-1...-1...-4
.-1....0....3...-1...-1...-1....0....3...-1...-1....0....1....1...-1....0...-1
..1....3....3....1...-1....1....5....6....2....6....1....2....1....4....2....6
..5....3....5....8....8....5....6....8....3....6....3....5....5....6....6....6
..7....8....6....9....9....6....7....8....6....7....8....8....8....8....7....7

Crossrefs

Sequence in context: A220334 A221295 A220687 * A165809 A332069 A237804

Adjacent sequences: A188237 A188238 A188239 * A188241 A188242 A188243

Keyword

nonn

Author

R. H. Hardin Mar 24 2011

Status

approved