A200055 Number of -6..6 arrays x(0..n-1) of n elements with zero sum and elements alternately strictly increasing and strictly decreasing

1, 12, 78, 546, 3914, 28554, 211242, 1577878, 11867186, 89815404, 682642050, 5211283212, 39897460856, 306446600454, 2358644800468, 18199380449274, 140644480480176, 1089068472750998, 8443172123261506, 65564035662489652

Offset

1,2

Comments

Column 6 of A200057

Links

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

Example

Some solutions for n=6
.-2....0...-3...-1...-3....5...-2....5....2....1...-3....0....4...-6...-1...-5
..4....5...-5...-2....1...-3....5...-5....1....0....0...-1...-3....3....0....1
.-5...-3....4....1...-6....1...-6....2....5....1...-1....1....1...-4...-2...-6
..4...-2....2...-3....6...-1....5...-2...-6...-3....2...-2...-6....3....5....3
.-5...-4....5....6....0....1...-4....1....1....4...-3....3....6....1...-2....1
..4....4...-3...-1....2...-3....2...-1...-3...-3....5...-1...-2....3....0....6

Crossrefs

Sequence in context: A227707 A189493 A199492 * A230520 A030116 A200036

Adjacent sequences: A200052 A200053 A200054 * A200056 A200057 A200058

Keyword

nonn

Author

R. H. Hardin Nov 13 2011

Status

approved