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A007508 Number of twin primes < 10^n.
(Formerly M1855)
+0
29
2, 8, 35, 205, 1224, 8169, 58980, 440312, 3424506, 27412679, 224376048, 1870585220, 15834664872, 135780321665, 1177209242304, 10304185697298, 90948839353159, 808675888577436 (list; graph; listen)
OFFSET

1,1

COMMENT

"At the present time (2001), Thomas Nicely has reached pi_2(3*10^15) and his value is confirmed by Pascal Sebah who made a new computation from scratch and up to pi_2(5*10^15) [ = 5357875276068] with an independent implementation."

Though the first paper contributed by D. A. Goldston was reported to be flawed, the more recent one (with other coauthors) maintains and substantiates the result. - Lekraj Beedassy (blekraj(AT)yahoo.com), Aug 19 2005

REFERENCES

N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

T. R. Nicely, Enumeration to 10^14 of the twin primes and Brun's constant, Virginia Journal of Science, 46:3 (Fall, 1995), 195-204.

P. Ribenboim, The Book of Prime Number Records. Springer-Verlag, NY, 2nd ed., 1989, p. 202.

LINKS

R. F. Arenstorf, There Are Infinitely Many Prime Twins

R. P. Brent, Irregularities in the distribution of primes and twin primes

C. K. Caldwell, The Prime Glossary, Twin prime conjecture

T. H. Chan, A note on Primes in Short Intervals

J. Derbyshire, Goldston & Yildirim's Result

P. Erdos, Some Unsolved Problems

G. H. Gadiyar & R. Padma, Renormalisation and the density of prime pairs

G. H. Gadiyar & R. Padma, Ramanujan-Fourier series, the Wiener-Khintchine formula and the distribution of prime pairs

D. A. Goldston, J. Pintz & C. Y. Yildirim, Primes in Tuples, I

D. A. Goldston, J. Pintz & C. Y. Yildirim, Small Gaps Between Primes, II

D. A. Goldston, J. Pintz & C. Y. Yildirim, The Path to Recent Progress on Small Gaps Between Primes

D. A. Goldston & C. Y. Yildirim, Small Gaps Between Primes, I

D. A. Goldston & C. Yildirim, Small gaps between consecutive primes

D. A. Goldston et al., Small gaps between primes or almost primes

D. A. Goldston et al., Small Gaps between Primes Exist

Xavier Gourdon and Pascal Sebah, Introduction to Twin Primes and Brun's Constant

A. Granville & K. Soundararajan, On the error in Goldston and Yildirim's "Small gaps between consecutive primes"

P. F. Kelly & F. Pilling, Characterization of the Distribution of Twin Primes

P. F. Kelly & T. Pilling, Implications of a New Characterization of the Distribution of Twin Primes

P. F. Kelly & T. Pilling, Discrete Reanalysis of a New Model of the Distribution of Twin Primes

Thomas R. Nicely, Home page. Has extensive tables.

Nova Science, Twin Prime Conjecture

Tomas Oliveira e Silva, Tables of values of pi(x) and of pi2(x) [From M. F. Hasler (MHasler(AT)univ-ag.fr), Dec 18 2008]

J. Richstein, Computing the number of twin primes up to 10^14

J. Richstein, Computing the number of twin primes up to 10^14

K. Soundararajan, The distribution of prime numbers

K. Soundararajan, Small gaps between prime numbers:The work of Goldston-Pintz-Yildirim

K. Soundararajan, Small gaps between prime numbers:The work of Goldston-Pintz-Yildirim

Eric Weisstein's World of Mathematics, Link to a section of The World of Mathematics.

Eric Weisstein, Mathworld Headline News, Twin Primes Proof Proffered

M. Wolf, Some Remarks on the Distribution of twin Primes

C. Yildirim & D. Goldston, Small gaps between consecutive primes

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

FORMULA

Partial sums of A070076(n). - Lekraj Beedassy (blekraj(AT)yahoo.com), Jun 11 2004

CROSSREFS

Cf. A001097.

Adjacent sequences: A007505 A007506 A007507 this_sequence A007509 A007510 A007511

Sequence in context: A030820 A030972 A020009 this_sequence A122674 A076122 A123290

KEYWORD

nonn,nice,hard

AUTHOR

N. J. A. Sloane (njas(AT)research.att.com), Robert G. Wilson v (rgwv(AT)rgwv.com)

EXTENSIONS

pi2(10^15) due to Nicely and Szymanski, contributed by Eric Weisstein (eric(AT)weisstein.com)

pi2(10^16) due to Pascal Sebah, contributed by Robert G. Wilson v (rgwv(AT)rgwv.com), Aug 22 2002

Added a(17)-a(18) computed by Tomas Oliveira e Silva and link to his web site. M. F. Hasler (MHasler(AT)univ-ag.fr), Dec 18 2008

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Last modified November 8 20:39 EST 2009. Contains 166234 sequences.


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