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A188362 Number of arrangements of 7 numbers x(i) in -n..n with the sum of x(i)*x(i+1) equal to zero 0
627, 9153, 49747, 181449, 480363, 1171345, 2295051, 4409889, 7651651, 12818961, 19584123, 30982585, 44149827, 63627969, 89493523, 123568713 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Row 6 of A188358

LINKS

Table of n, a(n) for n=1..16.

EXAMPLE

Some solutions for n=4

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

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

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

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

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

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

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

CROSSREFS

Sequence in context: A129974 A031703 A158382 * A098260 A224603 A261708

Adjacent sequences:  A188359 A188360 A188361 * A188363 A188364 A188365

KEYWORD

nonn

AUTHOR

R. H. Hardin Mar 28 2011

STATUS

approved

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Last modified May 30 11:39 EDT 2020. Contains 334724 sequences. (Running on oeis4.)