%I #12 Mar 12 2017 22:51:21
%S 1,3,7,18,38,100,224,600,1498,4124,11054,31347,87887,253251,727867,
%T 2117551,6159994,18022052,52757222,154874172,454989753,1338737083,
%U 3941860229,11618101775,34264747423,101127761931,298632667837,882370316215,2608423280534,7714578529582
%N Number of n-bead necklaces labeled with numbers 1..n allowing reversal, with no adjacent beads differing by more than 1.
%H Andrew Howroyd, <a href="/A208715/b208715.txt">Table of n, a(n) for n = 1..100</a>
%e All solutions for n=3:
%e ..2....2....1....3....2....1....1
%e ..2....2....1....3....3....2....1
%e ..2....3....2....3....3....2....1
%Y Diagonal of A208721.
%K nonn
%O 1,2
%A _R. H. Hardin_, Mar 01 2012
%E a(17)-a(30) from _Andrew Howroyd_, Mar 03 2017