A189950 - OEIS

%I #11 Feb 12 2026 15:15:37

%S 20,103,1350,22220,327880,4678100,68081570,1012894742,15245829657,

%T 230937539015,3515809056902,53766069905706,825394005427540,

%U 12711935460761503,196311914160978767,3038824326513268799

%N 1/4 the number of arrangements of n+1 nonzero numbers x(i) in -8..8 with the sum of sign(x(i))*(|x(i)| mod x(i+1)) equal to zero.

%C Column 8 of A189951.

%H R. H. Hardin, <a href="/A189950/b189950.txt">Table of n, a(n) for n = 1..65</a>

%e Some solutions with n=3

%e .-6...-6...-5....7....1...-2...-3....7...-6....7....3....6....1....7...-2....5

%e .-6...-5....2...-2....4....8....2....3...-1....2...-5...-3....4...-1....8....2

%e .-1....2....1...-1...-5...-6...-5...-4....6...-3....7....8...-5....6...-6...-1

%e ..1....7...-3....2...-6....1....4...-5...-5...-4....5....5...-8....5...-3....3

%Y Cf. A189951.

%K nonn

%O 1,1

%A _R. H. Hardin_, May 02 2011