%I #11 Nov 03 2019 16:03:55
%S 0,0,0,0,2,9,50,206,862,3384,13250,50852,194810,741884,2823712,
%T 10735998,40843370,155483873,592614050,2261585918,8643288808,
%U 33080772468,126797503250,486710415710,1870851589552,7201012694120,27752927349880,107092389688830,413729680838330
%N Number of n-bead necklace structures which are not self-equivalent under a nonzero rotation using exactly four different colored beads.
%C Permuting the colors does not change the structure.
%H Andrew Howroyd, <a href="/A328741/b328741.txt">Table of n, a(n) for n = 1..200</a>
%F a(p) = A056297(p) = A056305(p) for prime p.
%e For n=6, the 9 necklace structures are: aaabcd, aabacd, aabcad, aabbcd, aabcbd, aabcdb, aacbdb, ababcd, abacbd.
%Y Column 4 of A327693.
%Y Cf. A056297, A056305, A328740, A328743.
%K nonn
%O 1,5
%A _Andrew Howroyd_, Oct 26 2019