|
Search: id:A115115
|
|
|
| A115115 |
|
Number of 3-asymmetric rhythm cycles: binary necklaces of length 3n subject to the restriction that for any k if the k-th bead is of color 1 then the (k+n)-th and (k+2n)-th beads (modulo 3n) are of color 0. |
|
+0
2
|
|
| 2, 4, 8, 24, 70, 232, 782, 2744, 9710, 34990, 127102, 466152, 1720742, 6391714, 23860936, 89479864, 336860182, 1272587758, 4822419422, 18325211326, 69810262088, 266548336954, 1019836872142, 3909374909672, 15011998757958
(list; graph; listen)
|
|
|
OFFSET
|
1,1
|
|
|
LINKS
|
R. W. Hall and P. Klingsberg, Asymmetric Rhythms, Tiling Canons and Burnside's Lemma,Bridges Proceedings, pp. 189-194, 2004 (Winfield, Kansas).
R. W. Hall and P. Klingsberg, Asymmetric Rhythms and Tiling Canons, Preprint, 2004.
|
|
FORMULA
|
a(n)=(Sum_{d|n}phi(3d)+Sum_{d|n, (3, d)=1}phi(d)4^(n/d))/(3n), where phi(n) is the Euler function A000010.
|
|
CROSSREFS
|
Cf. A115114.
Sequence in context: A078223 A116719 A114900 this_sequence A026097 A067646 A152875
Adjacent sequences: A115112 A115113 A115114 this_sequence A115116 A115117 A115118
|
|
KEYWORD
|
easy,nonn
|
|
AUTHOR
|
Valery A. Liskovets (liskov(AT)im.bas-net.by), Jan 17 2006
|
|
|
Search completed in 0.002 seconds
|
