login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A067393 Number of nonprimes among the numbers in {1,2,3,...,n!} which are relatively prime to n!. 0
1, 1, 1, 1, 1, 5, 67, 481, 4989, 51979, 570755, 5865449, 74226518, 904772855, 13111019601, 202135743076, 3307158697867, 53256981940267, 974755766640247, 17629139875485487, 357191085875727470, 7585952737111971220, 168542590546266903340, 3718034609300727209976 (list; graph; refs; listen; history; text; internal format)
OFFSET
0,6
LINKS
FORMULA
a(n)=phi(n!)-pi(n!)+pi(n)= A000010(n!)-A000720(n!)+A000720(n).
EXAMPLE
For n=5, n!=120, a(5)=phi(120)-pi(120)+pi(5)=32-30+3=5; the 5 nonprimes are 1,49,77,91,119.
MATHEMATICA
a[n_] := EulerPhi[ n! ]-PrimePi[ n! ]+PrimePi[n]
CROSSREFS
Sequence in context: A142009 A226412 A226343 * A212731 A316146 A113265
KEYWORD
nonn
AUTHOR
Labos Elemer, Jan 22 2002
EXTENSIONS
a(18)-a(19) from Donovan Johnson, Mar 24 2011
a(20)-a(23) from Giovanni Resta, Oct 29 2019
STATUS
approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified July 23 19:18 EDT 2024. Contains 374553 sequences. (Running on oeis4.)