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A293772 Let P be the sequence of distinct lattice points defined by the following rules: P(1) = (0,0), P(2) = (1,0), and for any i < j < k, P(k) does not lie on the vector (P(i), P(j)), and for any n > 2, P(n) is the closest lattice point to P(n-1) such that the angle of the vectors (P(n-2), P(n-1)) and (P(n-1), P(n)), say t, satisfies 0 < t <= Pi/2, and in case of a tie, minimize the angle t; a(n) = X-coordinate of P(n). 2
0, 1, 1, 0, -1, -1, 0, 2, 2, 1, 0, -1, -2, -2, -1, 1, 3, 3, 2, 1, -1, -2, -3, -3, -2, -1, 1, 2, 4, 4, 3, 2, 0, -3, -4, -4, -3, -2, -1, 1, 2, 3, 4, 4, 3, 1, -2, -5, -5, -4, -1, 0, 1, 3, 4, 5, 5, 4, 3, 1, -2, -3, -6, -6, -5, -3, 0, 1, 2, 3, 4, 5, 5, 4, 2, -1, -4 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,8
COMMENTS
See A293773 for the corresponding Y-coordinates.
The following diagram depicts the angle t cited in the name:
. P(n)* .
. | t .
. | .
. | .
. |.
. P(n-1)*
. /
. /
. P(n-2)*
This sequence has building features in common with A293680.
The representation of the first thousands points of the sequence shows a spiral.
LINKS
EXAMPLE
See representation of first points in Links section.
PROG
(PARI) See Links section.
CROSSREFS
Sequence in context: A253262 A015504 A055892 * A293680 A293539 A292469
KEYWORD
sign,look
AUTHOR
Rémy Sigrist, Oct 16 2017
STATUS
approved

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Last modified December 4 16:44 EST 2023. Contains 367563 sequences. (Running on oeis4.)