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单词 Prime Counting Function
释义

Prime Counting Function

The function giving the number of Primes less than (Shanks 1993, p. 15). The first few values are 0, 1, 2, 2,3, 3, 4, 4, 4, 4, 5, 5, 6, 6, 6, ... (Sloane's A000720). The following table gives the values of for powers of 10(Sloane's A006880; Hardy and Wright 1979, p. 4; Shanks 1993, pp. 242-243; Ribenboim 1996, p. 237). Deleglise and Rivat (1996) havecomputed .

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

is incorrectly given as 50,847,478 in Hardy and Wright (1979). The prime counting function can be expressed byLegendre's Formula, Lehmer's Formula, Mapes' Method, or Meissel's Formula. A brief history ofattempts to calculate is given by Berndt (1994). The following table is taken from Riesel (1994).

MethodTimeStorage
Legendre
Meissel
Lehmer
Mapes'
Lagarias-Miller-Odlyzko
Lagarias-Odlyzko 1
Lagarias-Odlyzko 2


A modified version of the prime counting function is given by




where is the Möbius Function and is the Riemann-Mangoldt Function.


The notation is also used to denote the number of Primes of the form (Shanks 1993, pp. 21-22).Groups of Equinumerous values of include (, ), (, ),(, , , ), (, ), (, , , , , ), (, , , ), (, , , , , ), and so on. The values of for small are given in the following table for the first fewpowers of ten (Shanks 1993).

1212
11131113
80878087
611617609619
4784480747834808
39231392663917539322
332194332384332180332398

0210
5775
40474238
306309310303
2387241224022390
19617196221966519593
166104166212166230166032

11
1112
8086
611616
47844806
3923139265

011010
345354
282730262927
203203209202211200
159315841613160116041596
130631306513105130691310513090

0111
5766
37444343
295311314308
2384240923992399
19552196531962319669
165976166161166204166237

Note that since , , , and are Equinumerous,

 
 

are also equinumerous.


Erdös proved that there exist at least one Prime of the form and at least one Prime of theform between and for all .


The smallest such that for , 3, ... are 2, 27, 96, 330, 1008, ... (Sloane's A038625), and thecorresponding are 1, 9, 24, 66, 168, 437, ... (Sloane's A038626). The number of solutions of for, 3, ... are 4, 3, 3, 6, 7, 6, ... (Sloane's A038627).

See also Bertelsen's Number, Equinumerous, Prime Arithmetic Progression, Prime Number Theorem, Riemann Weighted Prime-Power Counting Function


References

Berndt, B. C. Ramanujan's Notebooks, Part IV. New York: Springer-Verlag, pp. 134-135, 1994.

Brent, R. P. ``Irregularities in the Distribution of Primes and Twin Primes.'' Math. Comput. 29, 43-56, 1975.

Deleglise, M. and Rivat, J. ``Computing : The Meissel, Lehmer, Lagarias, Miller, Odlyzko Method.'' Math. Comput. 65, 235-245, 1996.

Finch, S. ``Favorite Mathematical Constants.'' http://www.mathsoft.com/asolve/constant/hrdyltl/hrdyltl.html

Forbes, T. ``Prime -tuplets.'' http://www.ltkz.demon.co.uk/ktuplets.htm.

Guiasu, S. ``Is There Any Regularity in the Distribution of Prime Numbers at the Beginning of the Sequence of Positive Integers?'' Math. Mag. 68, 110-121, 1995.

Hardy, G. H. and Wright, E. M. An Introduction to the Theory of Numbers, 5th ed. Oxford, England: Clarendon Press, 1979.

Lagarias, J.; Miller, V. S.; and Odlyzko, A. ``Computing : The Meissel-Lehmer Method.'' Math. Comput. 44, 537-560, 1985.

Lagarias, J. and Odlyzko, A. ``Computing : An Analytic Method.'' J. Algorithms 8, 173-191, 1987.

Mapes, D. C. ``Fast Method for Computing the Number of Primes Less than a Given Limit.'' Math. Comput. 17, 179-185, 1963.

Meissel, E. D. F. ``Über die Bestimmung der Primzahlmenge innerhalb gegebener Grenzen.'' Math. Ann. 2, 636-642, 1870.

Ribenboim, P. The New Book of Prime Number Records, 3rd ed. New York: Springer-Verlag, 1996.

Riesel, H. ``The Number of Primes Below .'' Prime Numbers and Computer Methods for Factorization, 2nd ed. Boston, MA: Birkhäuser, pp. 10-12, 1994.

Shanks, D. Solved and Unsolved Problems in Number Theory, 4th ed. New York: Chelsea, 1993.

Sloane, N. J. A. Sequences A038625,A038626,A038627,A000720/M0256, andA006880/M3608in ``An On-Line Version of the Encyclopedia of Integer Sequences.''http://www.research.att.com/~njas/sequences/eisonline.html.

Vardi, I. Computational Recreations in Mathematica. Reading, MA: Addison-Wesley, pp. 74-76, 1991.

Wolf, M. ``Unexpected Regularities in the Distribution of Prime Numbers.'' http://rose.ift.uni.wroc.pl/~mwolf/.


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