A334484 a(n) is the Y-coordinate of the n-th point of the Sierpinski arrowhead curve; sequence A334483 gives X-coordinates.
0, 0, 1, 2, 3, 3, 2, 1, 0, 0, 1, 1, 0, 0, 1, 2, 2, 3, 4, 5, 5, 4, 4, 5, 6, 6, 7, 8, 9, 9, 8, 8, 9, 10, 10, 11, 12, 12, 13, 14, 15, 15, 14, 13, 12, 12, 11, 10, 10, 9, 8, 8, 9, 9, 8, 7, 6, 6, 5, 4, 4, 5, 5, 4, 3, 2, 2, 1, 0, 0, 1, 1, 0, 0, 1, 2, 3, 3, 2, 1, 0, 0
Offset: 0
Examples
The Sierpinski arrowhead curve starts (on a hexagonal lattice) as follows:
+
27\
\
+
/26
/
+----+
/24 25
/
+ +----+
23\ /20 19\
\ / \
+----+ +
22 21 /18
/
+----+ +
/4 5\ 17\
/ \ \
+ + +----+
3\ /6 16 15\
\ / \
+ + +----+ +
/2 7\ /10 11\ /14
/ \ / \ /
+----+ +----+ +----+
0 1 8 9 12 13
- hence a(3) = a(6) = a(15) = a(16) = 2.
Links
- Rémy Sigrist, Table of n, a(n) for n = 0..2187
- Rémy Sigrist, PARI program for A334484
- Wikipedia, Arrowhead curve
- Index entries for sequences related to coordinates of 2D curves
Programs
-
PARI
See Links section.
Comments