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 A108381 #2 Mar 30 2012 17:22:40 %S A108381 1,1,1,2,3,3,8,9,16,17,62,23,186,95,280,240,1963,225,6830,1091 %N A108381 Number of distinct magnitudes of the nonzero sums of distinct n-th roots of unity. %C A108381 There are 2^n sums of the n-th roots of unity. %H A108381 T. D. Noe, <a href="http://www.sspectra.com/math/RootSums.html">Sums of Roots of Unity Plots</a> %e A108381 a(4)=2 because the nonzero sums of 4th roots of unity have magnitude 1 or sqrt(2). %Y A108381 Cf. A103314 (number of subsets of the n-th roots of unity summing to zero). %K A108381 nonn %O A108381 1,4 %A A108381 _T. D. Noe_, Jun 01 2005