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 A326660 #20 Sep 16 2019 04:10:02 %S A326660 0,0,1,3,12,34,111,315,933,2622,7503,21033,59472,167118,472120, %T A326660 1332945,3777600,10720869,30516447,87032994,248820704,712743768, %U A326660 2045784183,5882367570,16942974048,48876558318,141204944529,408494941773,1183247473872,3431450670601 %N A326660 Number of n-bead asymmetric bracelets with exactly 3 different colored beads. %C A326660 Asymmetric bracelets are those primitive (period n) bracelets that when turned over are different from themselves. %H A326660 Andrew Howroyd, <a href="/A326660/b326660.txt">Table of n, a(n) for n = 1..200</a> %F A326660 a(n) = A032240(n) - 3*A032239(n) for n >= 3. %F A326660 Moebius transform of A305542. %e A326660 Case n = 4: There are 3 distinct asymmetric bracelets with exactly 3 colors which are aabc, abbc, abcc. %Y A326660 Column k=3 of A309651. %Y A326660 Cf. A032239, A032240, A056343, A056349, A305542, A326789. %K A326660 nonn %O A326660 1,4 %A A326660 _Andrew Howroyd_, Sep 12 2019