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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
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
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
KEYWORD
nonn
AUTHOR
R. H. Hardin, Nov 11 2011
STATUS
approved