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A334221
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.
3
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, 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, 6, 5, 5, 6, 7, 7, 6, 5, 4, 3, 3, 4, 5, 6, 7, 7, 6, 5, 5
OFFSET
0,6
FORMULA
A334188(a(n), A334220(n)) = n.
EXAMPLE
The "forward" branch of curve U starting from the origin is as follows:
|
6| 25..
| |
5| 24
| |
4| 21...22...23
| |
3| 20 15...14
| | | |
2| 5....6 19 16 13
| | | | | |
1| 4 7 18...17 12
| | | |
0| 0....1....2....3 8....9...10...11
---+----------------------------------------
y/x| 0 1 2 3 4 5 6 7
- hence a(5) = a(6) = a(13) = a(16) = a(19) = 2.
PROG
(PARI) See Links section.
CROSSREFS
Sequence in context: A016370 A334577 A219494 * A368842 A089069 A143535
KEYWORD
nonn,look
AUTHOR
Rémy Sigrist, Apr 19 2020
STATUS
approved