cp's OEIS Frontend

A209480 Number of n-bead necklaces labeled with numbers -3..3 allowing reversal, with sum zero and avoiding the patterns z z+1 z+2 and z z-1 z-2.

%I A209480 #6 Mar 12 2017 23:31:19
%S A209480 1,4,7,35,140,731,3740,20888,118137,687981,4059192,24292229,146840708,
%T A209480 895753665,5505619880,34065921090
%N A209480 Number of n-bead necklaces labeled with numbers -3..3 allowing reversal, with sum zero and avoiding the patterns z z+1 z+2 and z z-1 z-2.
%C A209480 Column 3 of A209485.
%e A209480 Some solutions for n=8:
%e A209480 .-3...-2...-3...-3...-3...-3...-3...-3...-3...-2...-3...-3...-3...-3...-3...-3
%e A209480 .-2...-2...-1...-1....0...-3....1....0...-1...-1...-2....0...-1...-1...-2...-3
%e A209480 ..0....0...-3....1...-1...-1...-1...-2....2...-2....0....3....2....0....1...-1
%e A209480 ..3....3....1....1....3...-1...-2....2....3...-1....1...-2....0...-3...-1....3
%e A209480 ..3...-2....2....1....2....3....1....3....1....3....3....2....2....2...-2....3
%e A209480 .-2....1....0....0....0....1....1....1....0....0....2....2....1...-1....3...-3
%e A209480 ..1....0....2....0...-3....2....2...-2...-3....0...-3...-3...-2....3....3....1
%e A209480 ..0....2....2....1....2....2....1....1....1....3....2....1....1....3....1....3
%K A209480 nonn
%O A209480 1,2
%A A209480 _R. H. Hardin_, Mar 09 2012