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%I
%S 1,7,93,1440,25225,476427,9501737,197197440,4219878330,92516600575,
%T 2068590840349,47010163129632,1083052539395723,25244912684662559,
%U 594388664281931925,14118181920797391360,337939791145403719897
%N Number of Lyndon words (aperiodic necklaces) with 3n beads of 3 colors, n beads of each color. One color labeled, the other two unlabeled.
%H <a href="/index/Lu#Lyndon">Index entries for sequences related to Lyndon words</a>
%F 1/(6n) * sum over d|n of {mu(n/d) * (3d)! / d!^3}.
%o (PARI) for(n=1,23,print(1/(6*n)*sumdiv(n,d,moebius(n/d)*(3*d)!/d!^3)))
%Y Inverse Witt transform of A006178.
%K nonn
%O 1,2
%A Lionel Levine (levine(AT)ultranet.com)
%E More terms from Jason Earls (zevi_35711(AT)yahoo.com), Aug 31 2001
%E Edited by _Christian G. Bower_, Aug 28 2002
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