Search: id:A002076 Results 1-1 of 1 results found. %I A002076 M0761 N0288 %S A002076 1,2,3,6,9,26,53,146,369,1002,2685,7434,20441,57046,159451,448686, %T A002076 1266081,3588002,10195277,29058526,83018783,237740670,682196949, %U A002076 1961331314,5648590737,16294052602,47071590147,136171497650 %N A002076 Number of equivalence classes of base-3 necklaces of length n, where necklaces are considered equivalent under both rotations as well as permutations of the symbols. %D A002076 N. J. Fine, Classes of periodic sequences, Illinois J. Math., 2 (1958), 285-302. %D A002076 N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence). %D A002076 N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence). %H A002076 N. J. A. Sloane, Maple code for this and related sequences %H A002076 Index entries for sequences related to necklaces %F A002076 Reference gives formula. %e A002076 E.g. a(2) = 2 as there are two equivalence classes of the 9 strings {00, 01,02,10,11,12,20,21,22 }: {00,11,22} form one equivalence class and {01,02,10,12,20,21} form the other. To see that (for example) 01 and 02 are equivalent, rotate 01 to 10 and then subtract 1 mod 3 from each element in 10 to get 02. %Y A002076 Cf. A000013, A000048, A002075. %Y A002076 Sequence in context: A056353 A111274 A133385 this_sequence A145761 A071714 A077753 %Y A002076 Adjacent sequences: A002073 A002074 A002075 this_sequence A002077 A002078 A002079 %K A002076 nonn,easy,nice %O A002076 1,2 %A A002076 N. J. A. Sloane (njas(AT)research.att.com). %E A002076 Better description and more terms from Mark Weston (mweston(AT)uvic.ca), Oct 06 2001 Search completed in 0.002 seconds