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 A208594 #12 Nov 01 2017 12:25:22
%S A208594 1,6,31,226,1761,14838,129823,1172298,10829443,101888166,972840341,
%T A208594 9402986626,91822503449,904557886854,8978540544171,89709076112442,
%U A208594 901536608361003,9106692124614666,92411996211470633,941636535001651066,9630568821834643189,98829095219423607906
%N A208594 Number of n-bead necklaces labeled with numbers -5..5 not allowing reversal, with sum zero.
%H A208594 Andrew Howroyd, <a href="/A208594/b208594.txt">Table of n, a(n) for n = 1..100</a>
%F A208594 a(n) = (1/n) * Sum_{d | n} totient(n/d) * A201549(d).
%e A208594 Some solutions for n=4:
%e A208594 .-3...-5...-3...-3...-4...-4...-5...-4...-2...-4...-4...-3...-3...-3...-3...-4
%e A208594 ..0....2....1....0....3...-2....2....4....1....3....4....0....5....3....2....0
%e A208594 ..3....5....2...-1....1....3...-2...-4....2....0...-1...-2....0...-1....1....4
%e A208594 ..0...-2....0....4....0....3....5....4...-1....1....1....5...-2....1....0....0
%t A208594 comps[r_, m_, k_] := Sum[(-1)^i*Binomial[r - 1 - i*m, k - 1]*Binomial[k, i], {i, 0, Floor[(r - k)/m]}]; a[n_Integer, k_] := DivisorSum[n, EulerPhi[n/#] comps[#*(k + 1), 2 k + 1, #] &]/n; a[n_] = a[n, 5]; Array[a, 22] (* _Jean-François Alcover_, Nov 01 2017, after _Andrew Howroyd_ *)
%Y A208594 Column 5 of A208597.
%K A208594 nonn
%O A208594 1,2
%A A208594 _R. H. Hardin_, Feb 29 2012
%E A208594 a(15)-a(22) from _Andrew Howroyd_, Mar 02 2017