|
Search: id:A124441
|
|
|
| A124441 |
|
a(n) = product{1<=k<=n/2, GCD(k,n)=1} k. |
|
+0
2
|
|
| 1, 1, 1, 1, 2, 1, 6, 3, 8, 3, 120, 5, 720, 15, 56, 105, 40320, 35, 362880, 189, 3200, 945, 39916800, 385, 9580032, 10395, 3203200, 19305, 87178291200, 1001, 1307674368000, 2027025, 65228800, 2027025, 4839284736, 85085
(list; graph; listen)
|
|
|
OFFSET
|
1,5
|
|
|
LINKS
|
Leroy Quet, Home Page (listed in lieu of email address)
|
|
EXAMPLE
|
The positive integers which are <= 9/2 and which are coprime to 9 are 1, 2 and 4. So a(9) = 1*2*4 = 8.
|
|
MAPLE
|
a:=proc(n) local b, k: b:=1: for k from 1 to floor(n/2) do if gcd(k, n)=1 then b:=b*k else b:=b fi od: b; end: seq(a(n), n=1..41); - Emeric Deutsch (deutsch(AT)duke.poly.edu), Nov 03 2006
|
|
MATHEMATICA
|
f[n_] := Times @@ Select[Range[Floor[n/2]], GCD[ #, n] == 1 &]; Table[f[n], {n, 36}] (*Chandler*)
|
|
CROSSREFS
|
Cf. A124442.
Sequence in context: A100014 A062566 A126265 this_sequence A026191 A050137 A086111
Adjacent sequences: A124438 A124439 A124440 this_sequence A124442 A124443 A124444
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
Leroy Quet Nov 01 2006
|
|
EXTENSIONS
|
More terms from Emeric Deutsch (deutsch(AT)duke.poly.edu), Nov 03 2006
|
|
|
Search completed in 0.002 seconds
|
