login
A328818
2 * x-coordinate of the points of a counterclockwise spiral on an hexagonal grid.
5
0, 2, 1, -1, -2, -1, 1, 3, 4, 3, 2, 0, -2, -3, -4, -3, -2, 0, 2, 4, 5, 6, 5, 4, 3, 1, -1, -3, -4, -5, -6, -5, -4, -3, -1, 1, 3, 5, 6, 7, 8, 7, 6, 5, 4, 2, 0, -2, -4, -5, -6, -7, -8, -7, -6, -5, -4, -2, 0, 2, 4, 6, 7, 8, 9, 10, 9, 8, 7, 6, 5, 3, 1, -1, -3, -5, -6, -7, -8, -9, -10, -9, -8, -7, -6, -5, -3, -1
OFFSET
0,2
COMMENTS
The Cartesian coordinates of the points of a counterclockwise spiral on an hexagonal grid are given by x(n) = a(n)/2 and by y(n)= A307012(n) * sqrt(3)/2.
FORMULA
a(n) = A307011(n) + A307013(n).
CROSSREFS
KEYWORD
sign
AUTHOR
Hugo Pfoertner, Oct 28 2019
STATUS
approved