login
This site is supported by donations to The OEIS Foundation.

 

Logo

Annual appeal: Please make a donation to keep the OEIS running! Over 6000 articles have referenced us, often saying "we discovered this result with the help of the OEIS".
Other ways to donate

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A055730 Number of primes <= 5^n. 0
0, 3, 9, 30, 114, 445, 1821, 7671, 33118, 145713, 650133, 2934858, 13375865, 61444585, 284140656, 1321453490, 6175961983, 28988040005, 136575061279, 645620925545, 3061129684411, 14552990145243, 69354801708586, 331251325552977, 1585299642009257, 7600886353341754, 36504944044424979, 175596829407110803, 845879609035799508, 4080206964520522386, 19705939422430380037, 95283357078617397618, 461221032128956299315 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

Table of n, a(n) for n=0..32.

Index entries for sequences related to numbers of primes in various ranges

FORMULA

a(n) = A000720(A000351(n)). - Michel Marcus, Aug 25 2014

MATHEMATICA

Table[PrimePi[5^n], {n, 0, 19}]

PROG

(PARI) a(n) = primepi(5^n); \\ Michel Marcus, Aug 25 2014

CROSSREFS

Cf. A006880, A007053 and A040014.

Sequence in context: A117428 A134168 A124427 * A120018 A091353 A279199

Adjacent sequences:  A055727 A055728 A055729 * A055731 A055732 A055733

KEYWORD

nonn

AUTHOR

Robert G. Wilson v, Jun 09 2000

EXTENSIONS

a(19) corrected by Henri Lifchitz, Nov 11 2012

a(20)-a(27) from Henri Lifchitz, Nov 11 2012

a(28)-a(32) from Henri Lifchitz, Aug 25 2014

Definition corrected by Jean-Claude Arbaut, Oct 07 2015

STATUS

approved

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

License Agreements, Terms of Use, Privacy Policy .

Last modified December 10 20:48 EST 2017. Contains 295856 sequences.