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%I #5 Mar 31 2012 12:36:12
%S 29,117,257,497,749,1205,1569,2161,2765,3589,4177,5377,6077,7253,8561,
%T 10017,10941,12837,13873,16017,17933,19845,21105,24097,25981,28245,
%U 30593,33729,35325,39397,41105,44449,47517,50517,53905,59009,61053,64405,68033
%N Number of arrangements of 4 numbers x(i) in -n..n with the sum of x(i)*x(i+1) equal to zero
%C Row 3 of A188358
%H R. H. Hardin, <a href="/A188359/b188359.txt">Table of n, a(n) for n = 1..135</a>
%e Some solutions for n=4
%e ..0....2...-3....3....2....3....0...-2....4...-1...-3....0....3...-4...-4....2
%e .-2....0....2...-2....0....0....1....0....0...-2...-2....4....0....0....3....0
%e ..0....0....3....3....3...-1....0....0...-3....1....3....0....3....2....4...-3
%e .-3...-2....0....4....0....0....1...-3....0....0....0...-1....0....0....0....0
%K nonn
%O 1,1
%A _R. H. Hardin_ Mar 28 2011