|
Search: id:A048862
|
|
|
| A048862 |
|
Number of primes in the reduced residue system of n-th primorial number(A002110). |
|
+0
5
|
|
| 0, 1, 7, 42, 338, 3242, 42324, 646021, 12283522, 300369786, 8028642999, 259488750732, 9414916809082
(list; graph; listen)
|
|
|
OFFSET
|
1,3
|
|
|
FORMULA
|
A000849(n) - A001221(A002110(n)) = A000720((A002110(n)) - n
|
|
EXAMPLE
|
n=3, 3rd primorial is 30, EulerPhi(30)=8, a(3)=8-1=7 since 1 is regarded here a nonprime. See A048597. n=4, 4th primorial is 210, size of its reduced residue system(RRS) is 48 of which 42 is prime and 6 is either composite or 1.
|
|
CROSSREFS
|
Cf. A002110, A000010, A000720, A048597, A007625, A048863.
Sequence in context: A127016 A073506 A025593 this_sequence A133669 A043064 A045800
Adjacent sequences: A048859 A048860 A048861 this_sequence A048863 A048864 A048865
|
|
KEYWORD
|
more,nonn
|
|
AUTHOR
|
Labos E. (labos(AT)ana.sote.hu)
|
|
|
Search completed in 0.002 seconds
|
