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A200059 Number of -n..n arrays x(0..4) of 5 elements with zero sum and elements alternately strictly increasing and strictly decreasing. 1
6, 68, 288, 840, 1948, 3914, 7074, 11862, 18732, 28244, 40970, 57598, 78816, 105444, 138284, 178282, 226362, 283598, 351026, 429852, 521230, 626492, 746910, 883944, 1038982, 1213616, 1409348, 1627896, 1870884, 2140158, 2437454, 2764750, 3123900 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Row 5 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) -2*a(n-5) +2*a(n-6) +a(n-8) -2*a(n-10) +a(n-11).

Empirical g.f.: 2*x*(3 + 28*x + 76*x^2 + 135*x^3 + 168*x^4 + 159*x^5 + 105*x^6 + 51*x^7 + 10*x^8 + x^9) / ((1 - x)^5*(1 + x)^2*(1 + x^2)*(1 + x + x^2)). - Colin Barker, May 17 2018

EXAMPLE

Some solutions for n=6:

..1...-1....3...-6...-4...-1....1....4....6...-3....5...-1....1....1....1...-2

..0....2...-6....2....3...-5....2...-6...-1...-5...-6....2...-1....5...-2....6

..1...-2....4...-3...-3....5...-6....3....3....5....6...-4....4...-2....2...-5

.-3....5...-5....4....4...-1....4...-3...-5....1...-4....2...-3...-1...-5....1

..1...-4....4....3....0....2...-1....2...-3....2...-1....1...-1...-3....4....0

CROSSREFS

Cf. A200057.

Sequence in context: A297435 A281058 A152390 * A183470 A281051 A006737

Adjacent sequences:  A200056 A200057 A200058 * A200060 A200061 A200062

KEYWORD

nonn

AUTHOR

R. H. Hardin, Nov 13 2011

STATUS

approved

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Last modified September 27 21:12 EDT 2021. Contains 347698 sequences. (Running on oeis4.)