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 A108417 #6 Nov 06 2019 17:50:59
%S A108417 0,1,2,6,8,10,36,14,64,72,180,22,720,26,924,600,2048,34,10800,38,
%T A108417 12240,2856,22572,46,144000
%N A108417 Number of subsets of the n-th roots of 1 with absolute value of sum = 1.
%C A108417 a(n) is divisible by n (rotation symmetry). a(n)/n differs from A107754 by a factor of 2 for odd n.
%t A108417 <<DiscreteMath`Combinatorica`; Table[Plus @@ Count[KSubsets[Range[n], k], q_List/;Chop[ -1+Abs[Plus @@ (E^((2.*Pi*I*q)/n))]] === 0], {n, 16}, {k, 0, n}]
%Y A108417 Row sums of A108416.
%Y A108417 Cf. A107754, A103314.
%K A108417 nonn,more
%O A108417 0,3
%A A108417 _Wouter Meeussen_, Jun 02 2005