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A203294
Number of arrays of 8 nondecreasing integers in -n..n with sum zero and equal numbers greater than zero and less than zero.
1
5, 15, 57, 188, 544, 1380, 3172, 6687, 13163, 24435, 43195, 73194, 119616, 189346, 291486, 437723, 642977, 925889, 1309647, 1822576, 2499166, 3380806, 4517000, 5966265, 7797585, 10091447, 12941561, 16456084, 20759580, 25994452, 32323204
OFFSET
1,1
COMMENTS
Row 4 of A203291.
LINKS
FORMULA
Empirical: a(n) = 3*a(n-1) -a(n-2) -3*a(n-3) +7*a(n-6) -3*a(n-7) -2*a(n-8) -2*a(n-9) -3*a(n-10) +7*a(n-11) -3*a(n-14) -a(n-15) +3*a(n-16) -a(n-17).
EXAMPLE
Some solutions for n=3
.-3....0...-3...-3...-3...-2...-3...-3...-3...-3...-2...-1...-3...-3...-3...-2
.-3....0....0...-3...-2....0...-2...-3...-3...-3...-2...-1...-2...-1...-3...-2
.-2....0....0...-3...-2....0...-1...-2...-1....0...-2...-1...-2....0...-3...-1
.-1....0....0....0...-1....0...-1...-2...-1....0....0....0....0....0...-3...-1
..1....0....0....0....1....0....1....2....2....0....0....0....0....0....3....1
..2....0....0....3....2....0....1....2....2....0....2....1....1....0....3....1
..3....0....0....3....2....0....2....3....2....3....2....1....3....1....3....1
..3....0....3....3....3....2....3....3....2....3....2....1....3....3....3....3
CROSSREFS
Cf. A203291.
Sequence in context: A309117 A307349 A343841 * A149589 A110614 A149590
KEYWORD
nonn
AUTHOR
R. H. Hardin, Dec 31 2011
STATUS
approved