|
Search: id:A060837
|
|
|
| A060837 |
|
List the positive rationals in the canonical order as in A038566 and apply the Sagher map to turn them into integers. |
|
+0
3
|
|
| 1, 2, 4, 3, 9, 8, 12, 18, 16, 5, 25, 6, 20, 72, 48, 50, 36, 7, 45, 75, 49, 32, 28, 80, 200, 98, 64, 27, 63, 147, 81, 10, 108, 288, 112, 150, 180, 392, 192, 162, 100, 11, 175, 245, 121, 24, 44, 90, 432, 800, 252, 294, 320, 648, 300, 242, 144, 13, 99, 675, 405, 363, 169, 14
(list; graph; listen)
|
|
|
OFFSET
|
1,2
|
|
|
COMMENT
|
The Sagher map sends Product p_i^e_i / Product q_i^f_i (p_i and q_i being distinct primes) to Product p_i^(2e_i) * Product q_i^(2f_i-1). This is multiplicative.
|
|
REFERENCES
|
Y. Sagher, Counting the rationals, Amer. Math. Monthly, 96 (1989), p. 823.
|
|
EXAMPLE
|
The first few rationals and their images are 1/1 -> 1, 1/2 -> 2, 2/1 -> 4, 1/3 -> 3, 3/1 -> 9, 1/4 -> 8, ...
|
|
CROSSREFS
|
Cf. A038566, A071970.
Adjacent sequences: A060834 A060835 A060836 this_sequence A060838 A060839 A060840
Sequence in context: A137442 A111390 A129596 this_sequence A019600 A096901 A100781
|
|
KEYWORD
|
nonn,nice,easy,mult
|
|
AUTHOR
|
njas, Jun 19 2002
|
|
EXTENSIONS
|
More terms from Antonio G. Astudillo (afg_astudillo(AT)hotmail.com), Jan 12 2003
|
|
|
Search completed in 0.002 seconds
|
