A203295 Number of arrays of 10 nondecreasing integers in -n..n with sum zero and equal numbers greater than zero and less than zero

6, 21, 104, 444, 1614, 5036, 13934, 34847, 80258, 172405, 349182, 672246, 1238648, 2196082, 3763716, 6258579, 10130162, 16003183, 24731962, 37466168, 55732478, 81531582, 117456262, 166829725, 233871176, 323887385, 443498894, 600898968

Offset

1,1

Comments

Row 5 of A203291

Links

R. H. Hardin, Table of n, a(n) for n = 1..210

Formula

Empirical: a(n) = 3*a(n-1) -a(n-2) -3*a(n-3) +a(n-4) -2*a(n-5) +5*a(n-6) +a(n-7) +a(n-8) -3*a(n-9) -7*a(n-10) +2*a(n-11) +2*a(n-12) +4*a(n-13) +2*a(n-14) +2*a(n-15) -7*a(n-16) -3*a(n-17) +a(n-18) +a(n-19) +5*a(n-20) -2*a(n-21) +a(n-22) -3*a(n-23) -a(n-24) +3*a(n-25) -a(n-26)

Example

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

Crossrefs

Sequence in context: A012773 A012662 A012418 * A318566 A083558 A060843

Adjacent sequences: A203292 A203293 A203294 * A203296 A203297 A203298

Keyword

nonn

Author

R. H. Hardin Dec 31 2011

Status

approved