This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A328740 #12 Nov 03 2019 16:03:47 %S A328740 0,0,0,1,5,13,43,116,335,920,2591,7173,20125,56260,158333,446098, %T A328740 1262225,3579227,10181479,29028405,82968695,237634700,682014587, %U A328740 1960951980,5647919640,16292680600,47069103545,136166476875,394418199725,1143821408316,3320790074371 %N A328740 Number of n-bead necklace structures which are not self-equivalent under a nonzero rotation using exactly three different colored beads. %C A328740 Permuting the colors does not change the structure. %H A328740 Andrew Howroyd, <a href="/A328740/b328740.txt">Table of n, a(n) for n = 1..200</a> %F A328740 a(p) = A056296(p) = A056304(p) for prime p >= 5. %e A328740 For n=5, the 5 necklace structures are: aaabc, aabac, aabbc, aabcb, ababc. %Y A328740 Column 3 of A327693. %Y A328740 Cf. A056296, A056304, A328741, A328742. %K A328740 nonn %O A328740 1,5 %A A328740 _Andrew Howroyd_, Oct 26 2019