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A200061
Number of -n..n arrays x(0..6) of 7 elements with zero sum and elements alternately strictly increasing and strictly decreasing
1
14, 472, 4224, 20978, 74338, 211242, 514168, 1115572, 2215290, 4099888, 7165376, 11941380, 19119208, 29580842, 44432366, 65037696, 93057524, 130487666, 179703518, 243503094, 325156994, 428455996, 557766736, 718083722, 915090720
OFFSET
1,1
COMMENTS
Row 7 of A200057
LINKS
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=6
..1....4....3...-2....3....6...-3....0...-6...-6...-3....0....4....0...-4....4
.-6....2...-1....0...-6...-6....2....2....6...-4....0...-1....3....4...-6...-6
..6....4....3...-3....2...-2...-4...-4...-4...-5...-6....0....5...-4....6....5
.-6...-6...-1....0...-3...-3....6....6....4....5....5...-3...-6....3....1...-4
..3....0....0...-1....4....6...-5...-5....0....3...-3....5...-4...-6....6....4
..0...-5...-4....6...-6...-3....5....6....1....5....5...-2...-6....4...-4...-5
..2....1....0....0....6....2...-1...-5...-1....2....2....1....4...-1....1....2
CROSSREFS
Sequence in context: A215787 A005790 A208563 * A171208 A331612 A275092
KEYWORD
nonn
AUTHOR
R. H. Hardin Nov 13 2011
STATUS
approved