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%I #15 Mar 26 2019 16:13:57
%S 0,1,1,0,-1,-1,0,2,1,-1,-2,-1,1,2,2,0,-2,-2,0,3,3,2,1,-1,-2,-3,-3,-2,
%T -1,1,2,3,3,0,-3,-3,0,4,2,-2,-4,-2,2,4,4,3,1,-1,-3,-4,-4,-3,-1,1,3,4,
%U 4,0,-4,-4,0,5,5,3,2,-2,-3,-5,-5,-3,-2,2,3,5,5,4,1
%N List coordinates (x,y) of the points in an hexagonal grid, sorted first by radial coordinate r and in case of ties, by polar angle 0 <= phi < 2*Pi in a polar coordinate system. Sequence gives the third coordinate in a barycentric coordinate system.
%C Cartesian coordinates (x,y) of the grid points are converted to barycentric coordinates (i,j,k) by i = x - y/sqrt(3), j = 2*y/sqrt(3), k = x + y/sqrt(3). The sequence gives k. i is given in A307014, j is given in A307016.
%H Hugo Pfoertner, <a href="/A307017/b307017.txt">Table of n, a(n) for n = 0..9060</a>, covering range r <= 50.
%Y Cf. A004016, A035019, A038590, A307014, A307016.
%K sign,look
%O 0,8
%A _Hugo Pfoertner_, Mar 21 2019
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