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A007053 Number of primes <= 2^n.
(Formerly M1018)
+0
36
0, 1, 2, 4, 6, 11, 18, 31, 54, 97, 172, 309, 564, 1028, 1900, 3512, 6542, 12251, 23000, 43390, 82025, 155611, 295947, 564163, 1077871, 2063689, 3957809, 7603553, 14630843, 28192750, 54400028, 105097565, 203280221, 393615806, 762939111, 1480206279, 2874398515, 5586502348, 10866266172, 21151907950, 41203088796, 80316571436, 156661034233, 305761713237, 597116381732, 1166746786182, 2280998753949, 4461632979717, 8731188863470, 17094432576778, 33483379603407, 65612899915304, 128625503610475 (list; graph; listen)
OFFSET

0,3

LINKS

N. J. A. Sloane, Table of n, a(n) for n=0..75 (from the web page of Tomas Oliveira e Silva)

Andrew R. Booker, The Nth Prime Page

Thomas R. Nicely, Some Results of Computational Research in Prime Numbers

Tomas Oliveira e Silva, Tables of values of pi(x) and of pi2(x)

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

EXAMPLE

pi(2^3)=4 since first 4 primes are 2,3,5,7 all <=2^3=8.

MATHEMATICA

Table[PrimePi[2^n], {n, 0, 46}] (* Robert G. Wilson v *)

CROSSREFS

Cf. A006880.

Sequence in context: A026658 A138688 A131298 this_sequence A005684 A018167 A115992

Adjacent sequences: A007050 A007051 A007052 this_sequence A007054 A007055 A007056

KEYWORD

nonn,nice

AUTHOR

njas, Mira Bernstein, Robert G. Wilson v (rgwv(AT)rgwv.com), S. W. Golomb

EXTENSIONS

More terms from j.mccranie(AT)comcast.net (Jud Mccranie).

Extended to n = 52 by Warren D. Smith (wds(AT)research.NJ.NEC.COM), Dec 11 2000, computed with Meissel-Lehmer-Legendre inclusion exclusion formula code he wrote back in 1985, recently re-run.

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Last modified July 4 18:25 EDT 2008. Contains 140886 sequences.


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