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%I #12 Apr 27 2020 20:40:08
%S 0,0,0,0,1,2,2,1,0,0,0,0,1,2,3,3,2,1,1,2,3,4,4,4,5,6,6,5,4,4,4,3,2,1,
%T 1,2,3,3,2,1,0,0,0,0,1,2,2,1,0,0,0,0,1,2,3,3,2,1,1,2,3,4,4,4,5,6,7,7,
%U 6,5,5,6,7,7,6,5,4,3,3,4,5,6,7,7,6,5,5
%N a(n) is the Y-coordinate of the point at n steps forward from the origine along the space filling curve U defined in A334188; sequence A334220 gives X-coordinates.
%H Rémy Sigrist, <a href="/A334221/b334221.txt">Table of n, a(n) for n = 0..8066</a>
%H Rémy Sigrist, <a href="/A334221/a334221.gp.txt">PARI program for A334221</a>
%H <a href="/index/Con#coordinates_2D_curves">Index entries for sequences related to coordinates of 2D curves</a>
%F A334188(a(n), A334220(n)) = n.
%e The "forward" branch of curve U starting from the origin is as follows:
%e |
%e 6| 25..
%e | |
%e 5| 24
%e | |
%e 4| 21...22...23
%e | |
%e 3| 20 15...14
%e | | | |
%e 2| 5....6 19 16 13
%e | | | | | |
%e 1| 4 7 18...17 12
%e | | | |
%e 0| 0....1....2....3 8....9...10...11
%e ---+----------------------------------------
%e y/x| 0 1 2 3 4 5 6 7
%e - hence a(5) = a(6) = a(13) = a(16) = a(19) = 2.
%o (PARI) See Links section.
%Y Cf. A334188, A334220.
%K nonn,look
%O 0,6
%A _Rémy Sigrist_, Apr 19 2020