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 A032166 #36 May 19 2019 13:02:07 %S A032166 11,55,440,3630,32208,295020,2783880,26793030,261994040,2593726344, %T A032166 25937424600,261535549220,2655593241840,27124986721140, %U A032166 278483211283552,2871858103075830,29732178147017280 %N A032166 Number of aperiodic necklaces of n beads of 11 colors. %C A032166 Number of monic irreducible polynomials of degree n over GF(11). # _Robert Israel_, Jan 07 2015 %H A032166 Vincenzo Librandi, <a href="/A032166/b032166.txt">Table of n, a(n) for n = 1..500</a> %H A032166 C. G. Bower, <a href="/transforms2.html">Transforms (2)</a> %H A032166 Y. Puri and T. Ward, <a href="http://www.cs.uwaterloo.ca/journals/JIS/VOL4/WARD/short.html">Arithmetic and growth of periodic orbits</a>, J. Integer Seqs., Vol. 4 (2001), #01.2.1. %H A032166 F. Ruskey, <a href="http://combos.org/necklace">Necklaces, Lyndon words, De Bruijn sequences, etc.</a> %H A032166 F. Ruskey, <a href="/A000011/a000011.pdf">Necklaces, Lyndon words, De Bruijn sequences, etc.</a> [Cached copy, with permission, pdf format only] %H A032166 <a href="/index/Lu#Lyndon">Index entries for sequences related to Lyndon words</a> %F A032166 "CHK" (necklace, identity, unlabeled) transform of 11, 0, 0, 0... %F A032166 a(n) = Sum_{d|n} mu(d)*11^(n/d)/n. %F A032166 G.f.: Sum_{k>=1} mu(k)*log(1/(1 - 11*x^k))/k. - _Ilya Gutkovskiy_, May 19 2019 %p A032166 f:= (n,p) -> add(numtheory:-mobius(d)*p^(n/d),d=numtheory:-divisors(n))/n: %p A032166 seq(f(n,11), n=1..100); # _Robert Israel_, Jan 07 2015 %t A032166 f[d_]:=MoebiusMu[d] 11^(n/d)/n; a[n_]:=Total[f/@Divisors[n]]; a[0]=1; Table[a[n], {n, 1, 30}] (* _Vincenzo Librandi_, Oct 14 2017 *) %o A032166 (PARI) a(n) = sumdiv(n, d, moebius(d)*11^(n/d))/n; \\ _Michel Marcus_, Jan 07 2015 %Y A032166 Column 11 of A074650. %K A032166 nonn %O A032166 1,1 %A A032166 _Christian G. Bower_