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A188350
Number of arrangements of n+1 numbers x(i) in -1..1 with the sum of x(i)*x(i+1) equal to zero
1
5, 15, 29, 91, 197, 627, 1477, 4671, 11693, 36487, 95405, 293695, 792525, 2412175, 6660989, 20097243, 56450693, 169229571, 481426405, 1436666475, 4126292293, 12275100443, 35511918037, 105423983379, 306684489749, 909271908483
OFFSET
1,1
COMMENTS
Column 1 of A188358
LINKS
EXAMPLE
Some solutions for n=4
..1....0....1...-1....0...-1....1....0....1...-1....0....0...-1...-1...-1....0
..0....0....0....0....0...-1....0....1....1....0....0....0....1....0....0....0
.-1...-1....1....1...-1....1...-1...-1....0...-1...-1...-1....1....0....0....1
.-1....0....0...-1....0....0....0...-1...-1....1....0...-1....0....0...-1....1
..1....1...-1...-1...-1....1...-1....0....1....1....0....1...-1...-1....0...-1
CROSSREFS
Sequence in context: A298025 A162525 A212871 * A268222 A285630 A078905
KEYWORD
nonn
AUTHOR
R. H. Hardin Mar 28 2011
STATUS
approved