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 A188253 Number of arrangements of 7 nonzero numbers x(i) in -n..n with the sum of x(i)*x(i+1) equal to zero 0
 40, 1284, 12692, 58824, 193232, 521124, 1142180, 2347608, 4323448, 7567844, 12129300, 19691552, 29057776, 42900188, 61593740, 86648240 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Row 5 of A188249 LINKS Table of n, a(n) for n=1..16. EXAMPLE Some solutions for n=4 ..1....2...-3...-1...-1....1...-1....4...-1....4...-1....4...-1....2....4....3 .-2....1....3....3...-2....1....3...-1....1....3....2....4...-3....3...-3...-2 ..4....4....4....3...-2....2....1...-4...-3...-3...-1....2...-3...-1...-4....1 ..2...-4...-4...-4...-2....3....2....3...-1....1....1...-2....4...-1...-1....4 .-3...-4...-4...-1....1...-2...-3....3....2....1....4....4....4...-2....4....2 .-4....3....3....2...-4....1...-4....3....1....1....1...-2...-2...-3...-3....4 ..1....2....3....2....1...-1....2...-2....1...-2...-3....2....4....4...-4...-3 CROSSREFS Sequence in context: A278381 A251202 A239189 * A049396 A135644 A165371 Adjacent sequences: A188250 A188251 A188252 * A188254 A188255 A188256 KEYWORD nonn AUTHOR R. H. Hardin Mar 25 2011 STATUS approved

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Last modified December 9 09:12 EST 2023. Contains 367690 sequences. (Running on oeis4.)