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 A077013 #3 Mar 30 2012 18:37:42
%S A077013 1,2,1,2,3,7,14,43,65,292,992,1154
%N A077013 Number of different argument values of vector sums generated by n vectors chosen from 2n (equally spaced) points around the unit circle. Arguments are considered different only up to rotation and reflection.
%C A077013 Arg[0] is taken as being equal to 0.
%e A077013 The arguments up to rotation and reflection for n=6 are {0, 0.17013, 0.206867, 0.293133, 0.32987, 0.385502, 0.5} or exactly {0, 1/2, 5/2-(6*ArcTan[2])/Pi, 5/2-(6*ArcTan[1+2/Sqrt[3]])/Pi, -3/2-(6*ArcTan[4-3*Sqrt[3]])/Pi, 3/2-(6*ArcTan[6- 3*Sqrt[3]])/Pi, -5/2+(6*ArcTan[4+3*Sqrt[3]])/Pi }
%Y A077013 Cf. A077078, A006840.
%K A077013 hard,nonn
%O A077013 1,2
%A A077013 _Wouter Meeussen_, Nov 28 2002