A199842 Number of -3..3 arrays x(0..n-1) of n elements with zero sum and no element more than one greater than the previous.

1, 4, 13, 42, 132, 428, 1393, 4561, 15032, 49889, 166542, 558744, 1883028, 6370957, 21628455, 73641852, 251385571, 860067894, 2948380732, 10124956970, 34823894885, 119940097035, 413612099138, 1427945022753, 4934850614704

Offset

1,2

Comments

Column 3 of A199847.

Links

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

Example

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

Crossrefs

Sequence in context: A307261 A287349 A000640 * A192910 A289807 A022029

Adjacent sequences: A199839 A199840 A199841 * A199843 A199844 A199845

Keyword

nonn

Author

R. H. Hardin, Nov 11 2011

Status

approved