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A334486
a(n) is the Y-coordinate of the n-th point of Gosper's flowsnake curve; sequence A334485 gives X-coordinates.
4
0, 0, 1, 1, 2, 2, 2, 1, 1, 2, 3, 3, 2, 3, 4, 5, 5, 5, 4, 4, 3, 3, 4, 4, 3, 2, 3, 4, 5, 5, 6, 6, 7, 7, 7, 6, 6, 7, 7, 8, 8, 8, 7, 6, 5, 4, 5, 6, 6, 5, 5, 6, 6, 7, 7, 7, 6, 6, 7, 8, 8, 7, 8, 9, 9, 10, 11, 11, 10, 11, 12, 13, 13, 13, 12, 12, 11, 11, 10, 9, 10, 10
OFFSET
0,5
COMMENTS
Coordinates are given on a hexagonal lattice with X-axis and Y-axis as follows:
Y
/
/
0 ---- X
EXAMPLE
The Gosper curve starts (on a hexagonal lattice) as follows:
. . . . . +---+---+ . . . .
\ \
. . +---+---+ +---+ + . . . .
\ \ / /
. . . +---+ +---+ + +---+ . .
/ \ \ \
. . +---+ +---+---+ + + + . .
/ \ \ \ / 49
. . + +---+ +---+ + + . . .
\ \ \ / /
. . + + +---+ + +---+ . . .
\ / \ / /10
. . . + +---+---+ + + . . .
25 \ \ /9
. . . . +---+ +---+ . . . .
/ 7 8
. . . . +---+ . . . . . .
0 1
- hence a(2) = a(3) = a(7) = a(8) = 1.
PROG
(PARI) See Links section.
CROSSREFS
Cf. A334485 (X coordinate), A229214 (direction +-1,2,3), A261180 (direction 0..5).
Sequence in context: A141604 A143996 A301562 * A356997 A171412 A248213
KEYWORD
nonn
AUTHOR
Rémy Sigrist, May 03 2020
STATUS
approved