A334235 a(n) is the X-coordinate of the point at n steps backward from the origin along the H-order curve defined in A334232; sequence A334236 gives Y-coordinates.

0, 0, 0, 0, 1, 1, 2, 2, 2, 2, 1, 1, 0, 0, 0, 0, 1, 1, 2, 2, 3, 3, 3, 3, 4, 4, 4, 4, 5, 5, 6, 6, 6, 6, 5, 5, 4, 4, 4, 4, 3, 3, 3, 3, 2, 2, 1, 1, 0, 0, 0, 0, 1, 1, 2, 2, 2, 2, 1, 1, 0, 0, 0, 0, 1, 1, 2, 2, 3, 3, 3, 3, 4, 4, 4, 4, 5, 5, 6, 6, 7, 7, 7, 7, 6, 6, 5

Offset: 0

Author

Rémy Sigrist, Apr 20 2020

Keywords

• nonn

Examples

			The "backward" branch of H-order curve starting from the origin is as follows:
    7|  -15..-16  -19..-20  -27..-28  -31
     |    |    |    |    |    |    |    |
    6|  -14  -17..-18  -21  -26  -29..-30
     |    |              |    |
    5|  -13  -10...-9  -22  -25
     |    |    |    |    |    |
    4|  -12..-11   -8  -23..-24
     |              |
    3|   -3...-4   -7
     |    |    |    |
    2|   -2   -5...-6
     |    |
    1|   -1
     |    |
    0|    0
  ---+----------------------------------------
  y/x|    0    1    2    3    4    5    6    7
- hence a(24) = a(25) = a(26) = a(27) = 4.
		

Links

• Rémy Sigrist, Table of n, a(n) for n = 0..8192
• Rémy Sigrist, PARI program for A334235
• Index entries for sequences related to coordinates of 2D curves

Crossrefs

Cf. A334232, A334236.

Programs

PARI

See Links section.

Formula

A334232(A334236(n), a(n)) = -n.