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!)
A227799 Number of composites removed in each step of the Sieve of Eratosthenes for 10^10. 3
4999999999, 1666666666, 666666666, 380952380, 207792207, 159840159, 112828348, 95013343, 74358271, 56409724, 50950713, 41311372, 36273411, 33742734, 30153115, 26170720, 23065826, 21931483, 19640105, 18256894, 17506397, 15954848, 14993294, 13813524, 12531256 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
COMMENTS
a(n) = the number of composites <= 10^10 for which the n-th prime is the least prime factor.
pi(sqrt(10^10)) = the number of terms of this sequence.
The sum of a(n) for n = 1..3401 = A000720(10^10) + A065855(10^10).
LINKS
EXAMPLE
a(1) = 10^10 \ 2 - 1.
a(2) = 10^10 \ 3 - 10^10 \ (2*3) - 1.
a(3) = 10^10 \ 5 - 10^10 \ (2*5) - 10^10 \ (3*5) + 10^10 \ (2*3*5) - 1.
a(4) = 10^10 \ 7 - 10^10 \ (2*7) - 10^10 \ (3*7) - 10^10 \ (5*7) + 10^10 \ (2*3*7) + 10^10 \ (2*5*7) + 10^10 \ (3*5*7) - 10^10 \ (2*3*5*7) - 1.
CROSSREFS
Sequence in context: A233615 A217146 A072018 * A216013 A158726 A338394
KEYWORD
nonn,fini
AUTHOR
Eric F. O'Brien, Jul 31 2013
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 March 29 08:01 EDT 2024. Contains 371265 sequences. (Running on oeis4.)