cp's OEIS Frontend

A208669 Number of 2n-bead necklaces labeled with numbers 1..6 allowing reversal, with neighbors differing by exactly 1.

%I A208669 #10 Mar 20 2017 09:50:17
%S A208669 5,9,16,32,65,152,360,937,2512,7034,20124,58899,174408,522453,1576468,
%T A208669 4787425,14607763,44758541,137607258,424343533,1311982883,4065937220,
%U A208669 12627227963,39290663343,122470374536,382359843141,1195524220166,3743191124783
%N A208669 Number of 2n-bead necklaces labeled with numbers 1..6 allowing reversal, with neighbors differing by exactly 1.
%H A208669 Andrew Howroyd, <a href="/A208669/b208669.txt">Table of n, a(n) for n = 1..100</a>
%F A208669 a(n) = (2*A208725(n) + A090995(n))/4.
%e A208669 All solutions for n=3:
%e A208669 ..3....5....2....3....3....2....4....4....2....1....1....2....1....3....4....1
%e A208669 ..4....6....3....4....4....3....5....5....3....2....2....3....2....4....5....2
%e A208669 ..5....5....2....3....3....4....4....4....4....1....3....2....3....5....6....1
%e A208669 ..6....6....3....4....4....3....5....5....5....2....4....3....2....4....5....2
%e A208669 ..5....5....4....5....3....4....6....4....4....1....3....2....3....5....6....3
%e A208669 ..4....6....3....4....4....3....5....5....3....2....2....3....2....4....5....2
%Y A208669 Column 6 of A208671.
%K A208669 nonn
%O A208669 1,1
%A A208669 _R. H. Hardin_, Feb 29 2012
%E A208669 a(16)-a(28) from _Andrew Howroyd_, Mar 19 2017