A189956 - OEIS

%I #5 Mar 31 2012 12:36:16

%S 32,1152,13569,73992,280284,839968,2095080,4678100,9483181,17859030,

%T 31526421,53335818,86113621,134395470,203331437,299865250,431183908,

%U 608327784,840894817,1144932377,1534996553,2030482093,2648947079

%N 1/4 the number of arrangements of 7 nonzero numbers x(i) in -n..n with the sum of sign(x(i))*(|x(i)| mod x(i+1)) equal to zero

%C Row 6 of A189951

%H R. H. Hardin, <a href="/A189956/b189956.txt">Table of n, a(n) for n = 1..87</a>

%e Some solutions with n=3

%e ..2...-1....1...-2...-3....1...-1...-2....1...-2....1...-3...-1...-3...-3...-1

%e .-3...-2...-2....2...-1...-1....2...-2...-2...-2...-3....3...-2...-1....3....1

%e ..2....2...-1...-1....1...-3...-1....2....2....1....2...-1...-1....2....1....2

%e .-2...-3...-1...-3....2....2....1....2....2....3....1...-1....3....2....1...-1

%e ..2...-1...-1....1...-2....3...-1...-2...-1...-1....3....2...-2...-1...-3....3

%e .-1...-2...-3....3...-1...-1....1....2....2...-1...-3....1....1....1...-1....3

%e ..3...-2....3....1....3....1....2...-1...-2...-2....2....3...-2...-2...-2....3

%K nonn

%O 1,1

%A _R. H. Hardin_ May 02 2011