%I A055684
%S A055684 0,0,1,0,2,1,2,1,4,1,5,2,3,3,7,2,8,3,5,4,10,3,9,5,8,5,13,3,14,7,9,7,11,
%T A055684 5,17,8,11,7,19,5,20,9,11,10,22,7,20,9,15,11,25,8,19,11,17,13,28,7,29,
%U A055684 14,17,15,23,9,32,15,21,11,34,11,35,17,19,17,29,11
%N A055684 Number of different n-pointed stars.
%C A055684 Does not count rotations or reflections.
%D A055684 Mark A. Herkommer, "Number Theory, A Programmer's Guide," McGraw-Hill, 
               New York, 1999, page 58.
%H A055684 Alexander Bogomolny, <a href="http://www.cut-the-knot.org/Generalization/
               PolyStar.shtml">Polygons: formality and intuition.</a>. Includes 
               applet to draw star polygons.
%H A055684 Hugo Pfoertner, <a href="http://www.randomwalk.de/sequences/a055684.pdf">
               Star-shaped regular polygons up to n=25.</a>
%H A055684 Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/
               StarPolygon.html">Star Polygon.</a>
%F A055684 ( phi(n) -2 )/2 = A023022 -1.
%e A055684 The first star has five points and is unique. The next is the seven pointed 
               star and it comes in two varieties.
%p A055684 with(numtheory): A055684 := n->(phi(n)-2)/2;
%t A055684 Table[(EulerPhi[n]-2)/2, {n, 3, 50}]
%Y A055684 Cf. A023022.
%Y A055684 Cf. A053669 smallest skip increment, A102302 skip increment of densest 
               star polygon.
%Y A055684 Sequence in context: A164799 A072614 A067044 this_sequence A024559 A061797 
               A068341
%Y A055684 Adjacent sequences: A055681 A055682 A055683 this_sequence A055685 A055686 
               A055687
%K A055684 nonn,easy
%O A055684 3,5
%A A055684 Robert G. Wilson v (rgwv(AT)rgwv.com), Jun 09 2000