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 A002075 M1160 N0443 #18 Jan 29 2022 01:16:28
%S A002075 1,1,2,4,8,22,52,140,366,992,2684,7404,20440,56992,159440,448540,
%T A002075 1266080,3587610,10195276,29057520,83018728,237737984,682196948,
%U A002075 1961323740,5648590728,16294032160,47071589778,136171440600
%N A002075 Number of equivalence classes with primitive period n of base 3 necklaces, where necklaces are equivalent under rotation and permutation of symbols.
%D A002075 N. J. Fine, Classes of periodic sequences, Illinois J. Math., 2 (1958), 285-302.
%D A002075 N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).
%D A002075 N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
%H A002075 <a href="/index/Ne#necklaces">Index entries for sequences related to necklaces</a>
%F A002075 Reference gives formula.
%F A002075 Sequence A002076 can be found as follows: Let F3(n) = this sequence, F3*(n) = function from A002076. Then F3*(n) = Sum_{ d divides n } F3(d).
%Y A002075 Cf. A000013, A000048, A002076.
%K A002075 nonn,easy,nice
%O A002075 1,3
%A A002075 _N. J. A. Sloane_
%E A002075 Better description and more terms from Mark Weston (mweston(AT)uvic.ca), Oct 07 2001