A200061 - OEIS

A200061

Number of -n..n arrays x(0..6) of 7 elements with zero sum and elements alternately strictly increasing and strictly decreasing

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

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OFFSET

1,1

COMMENTS

Row 7 of A200057

LINKS

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

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

Adjacent sequences: A200058 A200059 A200060 * A200062 A200063 A200064

KEYWORD

nonn

AUTHOR

R. H. Hardin Nov 13 2011

STATUS

approved