|
Search: id:A038870
|
|
|
| A038870 |
|
Triangle read by rows: T(n,k) = number of orbits of order exactly k under doubling map which remain in a semicircle, with k dividing n. |
|
+0
2
|
|
| 0, 1, 1, 3, 1, 7, 1, 5, 11, 15, 1, 31, 1, 9, 21, 43, 55, 63, 1, 37, 91, 127, 1, 17, 85, 171, 239, 255, 1, 73, 439, 511, 1, 33, 137, 293, 341, 683, 731, 887, 991, 1023, 1, 661, 1387, 2047, 1, 65, 273, 585, 1189, 1365, 2731, 2907, 3511, 3823, 4031, 4095, 1
(list; graph; listen)
|
|
|
OFFSET
|
1,4
|
|
|
COMMENT
|
If alpha=exp(2i*pi*a(d,n)/(2^n - 1)), the orbit of alpha has period n and stays in the semi-circle of minimal argument alpha.
|
|
FORMULA
|
a(d, n)=Sum 2^[ nk/d ], k=0..{d-1}; (d, n)=1.
|
|
CROSSREFS
|
Cf. A038871.
Sequence in context: A038712 A065745 A117677 this_sequence A140435 A063754 A099749
Adjacent sequences: A038867 A038868 A038869 this_sequence A038871 A038872 A038873
|
|
KEYWORD
|
nonn,tabf,easy
|
|
AUTHOR
|
Francois Maurel (maurel(AT)sequoia.ens.fr)
|
|
|
Search completed in 0.002 seconds
|
