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%I #5 Mar 31 2012 12:36:11
%S 144,436,6376,43440,521124,4875112,55994544,591604824,6764014136,
%T 75116513672,862566555260,9803647311540,113184217957288,
%U 1302374837233636,15107289166289400,175125528108662876,2039302796727309112
%N Number of arrangements of n+2 nonzero numbers x(i) in -6..6 with the sum of x(i)*x(i+1) equal to zero
%C Column 6 of A188249
%H R. H. Hardin, <a href="/A188246/b188246.txt">Table of n, a(n) for n = 1..26</a>
%e Some solutions for n=4
%e .-6...-2...-2...-1....5....2....6...-1...-1...-2...-6....4....2...-6....6...-4
%e ..6...-1...-2....2...-1....3....3...-2...-6...-4...-3...-3....6....3....3...-2
%e ..3...-2....5....2....2....1....3...-6...-6....4....6...-6....4....6....3...-4
%e .-2...-1....3...-6...-1...-3...-1....3....3....4....5....4...-5...-1...-6....4
%e .-3....1...-1...-2...-3....6...-6....1...-3...-1...-3....2....2...-3....1....5
%e .-6...-5....6....1...-2....2....5....1....5....4....5....5...-3...-1...-3...-4
%K nonn
%O 1,1
%A _R. H. Hardin_ Mar 25 2011
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