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A203288 Number of arrays of 2n nondecreasing integers in -5..5 with sum zero and equal numbers greater than zero and less than zero 1
6, 35, 154, 544, 1614, 4206, 9880, 21363, 43136, 82267, 149456, 260438, 437670, 712512, 1127794, 1741011, 2628022, 3887553, 5646312, 8065104, 11345704, 15738920, 21553576, 29166921, 39036102, 51711323, 67850258, 88234392 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Column 5 of A203291

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..145

FORMULA

Empirical: a(n) = 4*a(n-1) -4*a(n-2) -2*a(n-3) +3*a(n-4) +7*a(n-6) -10*a(n-7) +a(n-8) -a(n-10) +10*a(n-11) -7*a(n-12) -3*a(n-14) +2*a(n-15) +4*a(n-16) -4*a(n-17) +a(n-18)

EXAMPLE

Some solutions for n=3

.-5...-3...-3...-3...-5...-5...-3...-5...-5...-3...-4...-5...-4...-5...-5...-3

.-4...-1...-2...-3...-4...-5...-2....0...-2...-3...-2...-4...-4...-5...-3...-3

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

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

..5....2....1....2....3....5....1....0....3....2....2....4....4....4....3....3

..5....2....4....5....5....5....5....5....3....4....3....5....4....4....5....3

CROSSREFS

Sequence in context: A161784 A027985 A078799 * A026957 A026987 A030532

Adjacent sequences: A203285 A203286 A203287 * A203289 A203290 A203291

KEYWORD

nonn

AUTHOR

R. H. Hardin Dec 31 2011

STATUS

approved

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Last modified January 27 12:24 EST 2023. Contains 359840 sequences. (Running on oeis4.)