A189945 - OEIS

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

%S 5,15,63,384,2393,13569,72744,393006,2206620,12731028,73789033,

%T 425385252,2445427072,14098065430,81698759400,475327637850,

%U 2770724256604,16165039535028,94402460826924,552050600817600,3233027830180059

%N 1/4 the number of arrangements of n+1 nonzero numbers x(i) in -3..3 with the sum of sign(x(i))*(|x(i)| mod x(i+1)) equal to zero

%C Column 3 of A189951

%H R. H. Hardin, <a href="/A189945/b189945.txt">Table of n, a(n) for n = 1..200</a>

%e Some solutions with n=4

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

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

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

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

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

%K nonn

%O 1,1

%A _R. H. Hardin_ May 02 2011