A188350 - OEIS

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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

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

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,1

COMMENTS

Column 1 of A188358

LINKS

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

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