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A199524 Number of -2..2 arrays x(0..n-1) of n elements with zero sum and no two consecutive zero elements 1
1, 4, 18, 72, 320, 1414, 6346, 28766, 131246, 602390, 2777638, 12857572, 59712940, 278096674, 1298309782, 6074112952, 28470828008, 133671581490, 628526085270, 2959291856816, 13950087683416, 65832860408434, 310987879638926 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Column 2 of A199530

LINKS

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

EXAMPLE

Some solutions for n=5

.-1....2....0...-1...-1....1...-2....2....1....1....0....0...-2....0...-1...-1

..0....1...-2....2....2....1....2...-2....0....2...-1....1....1....1....0...-2

.-2...-2....1....2....2....1...-2....2....1...-1...-1....1....2...-2....2....0

..1...-1....0...-2...-1...-2....2....0...-2....0....0...-1....1....2....1....2

..2....0....1...-1...-2...-1....0...-2....0...-2....2...-1...-2...-1...-2....1

CROSSREFS

Sequence in context: A307566 A117615 A267450 * A083693 A123476 A027905

Adjacent sequences:  A199521 A199522 A199523 * A199525 A199526 A199527

KEYWORD

nonn

AUTHOR

R. H. Hardin Nov 07 2011

STATUS

approved

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Last modified September 27 00:14 EDT 2020. Contains 337378 sequences. (Running on oeis4.)