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A092816 Number of Sophie Germain primes less than 10^n. 8
3, 10, 37, 190, 1171, 7746, 56032, 423140, 3308859, 26569515, 218116524, 1822848478, 15462601989, 132822315652 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Hardy-Littlewood conjecture: Number of Sophie Germain primes less than n ~ 2*C2*n/(log(n))^2, where C2 = 0.6601618158... is the twin prime constant (see A005597). The truth of the above conjecture would imply that there are an infinite number of Sophie Germain primes (which is also conjectured). - Robert G. Wilson v, Jan 31 2013

REFERENCES

P. Ribenboim, The Little Book of Big Primes, Springer-Verlag, New York, 1991, p. 228.

LINKS

Table of n, a(n) for n=1..14.

C. K. Caldwell, An amazing prime heuristic, Table 6.

Eric Weisstein's World of Mathematics, Sophie Germain Prime

CROSSREFS

Cf. A005384, A156874, A182265.

Sequence in context: A250307 A289990 A123636 * A078109 A149045 A149046

Adjacent sequences:  A092813 A092814 A092815 * A092817 A092818 A092819

KEYWORD

nonn

AUTHOR

Eric W. Weisstein, Mar 06 2004

EXTENSIONS

a(10) computed by Eric W. Weisstein, Nov 02 2005

a(11)-a(12) from Donovan Johnson, Jun 19 2010

a(13)-a(14) from Giovanni Resta, Sep 04 2017

STATUS

approved

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Last modified April 10 08:09 EDT 2021. Contains 342845 sequences. (Running on oeis4.)