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A334223
a(n) is the Y-coordinate of the point at n steps backward from the origine along the space filling curve U defined in A334188; sequence A334222 gives X-coordinates.
3
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, 6, 7, 8, 8, 8, 9, 10, 10, 9, 8, 8, 8, 8, 9, 10, 11, 11, 10, 9, 9, 10, 11, 12, 12, 12, 13, 14, 15, 15, 14, 13, 13, 14, 15, 15, 14, 13, 12, 11, 11, 12, 13
OFFSET
0,3
FORMULA
A334188(a(n), A334223(n)) = -n.
EXAMPLE
The "backward" branch of curve U starting from the origin is as follows:
| |
7| -15..-16 -21..-22 -31..-32 -37
| | | | | | | |
6| -14 -17 -20 -23 -30 -33 -36
| | | | | | | |
5| -13 -18..-19 -24 -29 -34..-35
| | | |
4| -12..-11..-10 -25 -28
| | | |
3| -3...-4 -9 -26..-27
| | | |
2| -2 -5 -8
| | | |
1| -1 -6...-7
| |
0| 0
---+-----------------------------------
y/x| 0 1 2 3 4 5 6
- hence a(10) = a(11) = a(12) = a(25) = a(28) = 4.
PROG
(PARI) See Links section.
CROSSREFS
Sequence in context: A131838 A274885 A287732 * A171414 A270921 A038529
KEYWORD
nonn
AUTHOR
Rémy Sigrist, Apr 19 2020
STATUS
approved