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Number of n-bead necklace structures which are not self-equivalent under a nonzero rotation using exactly four different colored beads.
4

%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