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A188248 Number of arrangements of n+2 nonzero numbers x(i) in -8..8 with the sum of x(i)*x(i+1) equal to zero 0
256, 816, 17040, 142532, 2347608, 28779900, 445304272, 6250275112, 95625385124, 1414314289436 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Column 8 of A188249

LINKS

Table of n, a(n) for n=1..10.

EXAMPLE

Some solutions for n=4

.-8....2....4...-2...-6....3...-5...-2....4...-7...-2....1...-5....7....7....2

.-5...-5....2...-5...-2...-2....2...-7....6....2....7...-6....4...-4...-4...-6

..4...-1...-2...-4...-7...-5...-2...-1....4....8...-7...-1...-8....8....7...-6

..3....3...-1...-6....6...-2...-7....1...-5...-1...-1....2...-4....7....8....5

..8....2...-6....6....8...-7...-8....4....7...-2...-8....2...-4....4....4....3

.-7....1....2...-3...-4....4....7...-6....1...-2...-6...-1...-1...-6...-8...-3

CROSSREFS

Sequence in context: A045057 A195091 A203450 * A209381 A236987 A236980

Adjacent sequences:  A188245 A188246 A188247 * A188249 A188250 A188251

KEYWORD

nonn

AUTHOR

R. H. Hardin Mar 25 2011

STATUS

approved

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Last modified December 22 22:37 EST 2014. Contains 252372 sequences.