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A339456
a(n) is the Y-coordinate of the n-th point of the space filling curve H defined in Comments section; A339455 gives X-coordinates.
2
0, 0, 1, 1, 0, -1, -1, 0, 0, 1, 2, 2, 3, 3, 2, 1, 1, 2, 2, 1, 0, -1, -2, -2, -1, -1, -2, -3, -3, -2, -2, -1, 0, 0, 1, 1, 0, -1, -1, 0, 0, 1, 2, 3, 4, 4, 5, 5, 4, 3, 3, 4, 4, 5, 6, 6, 7, 7, 6, 5, 5, 6, 6, 5, 4, 3, 2, 2, 3, 3, 2, 1, 1, 2, 2, 3, 4, 4, 5, 5, 4, 3
OFFSET
0,11
COMMENTS
We consider a hexagonal lattice with X-axis and Y-axis as follows:
Y
/
/
0 ---- X
We define the family {H_n, n > 0} as follows:
- T_1 contains the origin (0, 0) and (1, 0), in that order:
+-->--+
O
- for any n > 0, H_{n+1} is built from 4 copies of H_n connected with 2^(n+1) unit segments as follows:
+->-2->-+
\ /
^ v
\ /
+->-1->-+->-4->-+
O / \
v ^
/ \
+->-3->-+
- H is the limit of H_n as n tends to infinity,
- H visits once every unit segment (u, v) where u and v are lattice points and at least one of u or v belongs to the region { (x, y) | x > 0 or x + y > 0 }.
PROG
(PARI) See Links section.
CROSSREFS
Cf. A339455.
Sequence in context: A191860 A109973 A340488 * A220517 A369053 A340328
KEYWORD
sign,look
AUTHOR
Rémy Sigrist, Dec 06 2020
STATUS
approved