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A343643
Z-coordinate of points following the 3D square spiral defined in A343640.
7
0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, -1, -1, -1, -1, -1, -1, -1, -1, -1, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 2
OFFSET
0,28
COMMENTS
See A343640 for more information about this 3D generalization of the 2D Ulam type square spiral.
The sequence can be seen as a table with row lengths A010014, where A010014(r) is the number of points of Z^3 with sup-norm r.
The graph of this sequence oscillates with increasing amplitude and wave length.
LINKS
PROG
(PARI) A343643_vec=concat([[P[3]| P<-A343640_row(n)] | n<-[0..2]]) \\ From 0 up to n there are (2n+1)^3 points with 3 coordinates each.
CROSSREFS
Cf. A343640 (triples), A343641 and A343642 (list of X and Y-coordinates).
Cf. A343633 (variant using the Euclidean norm), A342563 (another variant).
Cf. A010014 (number of points on a shell with given radius => row lengths).
Sequence in context: A194294 A263110 A044927 * A044928 A362114 A274070
KEYWORD
sign,tabf
AUTHOR
M. F. Hasler, Apr 28 2021
STATUS
approved