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%I #16 May 27 2021 16:15:36
%S 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,
%T -2,-2,-2,-2,-2,-2,-2,-2,-2,-2,-2,-2,-2,-2,-2,-2,-2,-2,-2,-2,-2,-2,-2,
%U -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
%N Z-coordinate of points following the 3D square spiral defined in A343640.
%C See A343640 for more information about this 3D generalization of the 2D Ulam type square spiral.
%C 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.
%C The graph of this sequence oscillates with increasing amplitude and wave length.
%H Hugo Pfoertner, <a href="/A343643/b343643.txt">Table of n, a(n) for n = 0..9260</a>
%o (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.
%Y Cf. A343640 (triples), A343641 and A343642 (list of X and Y-coordinates).
%Y Cf. A343633 (variant using the Euclidean norm), A342563 (another variant).
%Y Cf. A010014 (number of points on a shell with given radius => row lengths).
%K sign,tabf
%O 0,28
%A _M. F. Hasler_, Apr 28 2021