Mertens Constant
The Mertens constant
, also known as the Hadamard-de la Vallee-Poussin constant, prime reciprocal constant (Bach and Shallit 1996, p. 234), or Kronecker's constant (Schroeder 1997), is a constant related to the twin primes constant and that appears in Mertens' second theorem,
 |
(1)
|
where the sum is over primes and
is a Landau symbol. This sum is the analog of
 |
(2)
|
where
is the Euler-Mascheroni constant (Gourdon and Sebah).
The constant is given by the infinite sum
![B_1=gamma+sum_(k=1)^infty[ln(1-p_k^(-1))+1/(p_k)]](https://mathworld.wolfram.com/images/equations/MertensConstant/NumberedEquation3.gif) |
(3)
|
where
is the Euler-Mascheroni constant and
is the
th prime (Rosser and Schoenfeld 1962; Hardy and Wright 1979; Le Lionnais 1983; Ellison and Ellison 1985), or by the limit
 |
(4)
|
According to Lindqvist and Peetre (1997), this was shown independently by Meissel in 1866 and Mertens (1874). Formula (3) is equivalent to
 |
(5)
|
which follows from (4) using the Mercator series for
with
.
is also given by the rapidly converging series
![B_1=gamma+sum_(m=2)^infty(mu(m))/mln[zeta(m)],](https://mathworld.wolfram.com/images/equations/MertensConstant/NumberedEquation6.gif) |
(6)
|
where
is the Riemann zeta function, and
is the Möbius function (Flajolet and Vardi 1996, Schroeder 1997, Knuth 1998).
The Mertens constant has the numerical value
 |
(7)
|
(OEIS A077761). Knuth (1998) gives 40 digits of
, and Gourdon and Sebah give 100 digits.
The product of
behaves asymptotically as
 |
(8)
|
(Hardy 1999, p. 57), where
is the Euler-Mascheroni constant and
is asymptotic notation, which is the Mertens theorem.
The constant
also occurs in the summatory function of the number of distinct prime factors
,
 |
(9)
|
(Hardy and Wright 1979, p. 355).
The related constant
(OEIS A083342) appears in the summatory function of the number of (not necessarily distinct) prime factors
,
 |
(14)
|
(Hardy and Wright 1979, p. 355), where
is the totient function and
is the Riemann zeta function.
Another related constant is
(OEIS A083343; Rosser and Schoenfeld 1962, Montgomery 1971, Finch 2003), which appears in another equivalent form of the Mertens theorem
 |
(17)
|
REFERENCES:
Bach, E. and Shallit, J. Algorithmic Number Theory, Vol. 1: Efficient Algorithms. Cambridge, MA: MIT Press, 1996.
Ellison, W. J. and Ellison, F. Prime Numbers. New York: Wiley, 1985.
Finch, S. R. "Meissel-Mertens Constants." §2.2 in Mathematical Constants. Cambridge, England: Cambridge University Press, pp. 94-98, 2003.
Flajolet, P. and Vardi, I. "Zeta Function Expansions of Classical Constants." Unpublished manuscript. 1996. http://algo.inria.fr/flajolet/Publications/landau.ps.
Gourdon, X. and Sebah, P. "Some Constants from Number Theory." http://numbers.computation.free.fr/Constants/Miscellaneous/constantsNumTheory.html.
Hardy, G. H. Ramanujan: Twelve Lectures on Subjects Suggested by His Life and Work, 3rd ed. New York: Chelsea, 1999.
Hardy, G. H. and Wright, E. M. "Mertens's Theorem." §22.8 in An Introduction to the Theory of Numbers, 5th ed. Oxford, England: Oxford University Press, pp. 351-353 and 355, 1979.
Ingham, A. E. The Distribution of Prime Numbers. London: Cambridge University Press, pp. 22-24, 1990.
Knuth, D. E. The Art of Computer Programming, Vol. 2: Seminumerical Algorithms, 3rd ed. Reading, MA: Addison-Wesley, 1998.
Landau, E. Handbuch der Lehre von der Verteilung der Primzahlen, 3rd ed. New York: Chelsea, pp. 100-102, 1974.
Le Lionnais, F. Les nombres remarquables. Paris: Hermann, p. 24, 1983.
Lindqvist, P. and Peetre, J. "On the Remainder in a Series of Mertens." Expos. Math. 15, 467-478, 1997.
Mertens, F. J. für Math. 78, 46-62, 1874.
Michon, G. P. "Final Answers: Numerical Constants." http://home.att.net/~numericana/answer/constants.htm#mertens.
Montgomery, H. L. Topics in Multiplicative Number Theory. New York: Springer-Verlag, 1971.
Rosser, J. B. and Schoenfeld, L. "Approximate Formulas for Some Functions of Prime Numbers." Ill. J. Math. 6, 64-94, 1962.
Schroeder, M. R. Number Theory in Science and Communication, with Applications in Cryptography, Physics, Digital Information, Computing, and Self-Similarity, 3rd ed. New York: Springer-Verlag, 1997.
Sloane, N. J. A. Sequences A077761, A083342, and A083343 in "The On-Line Encyclopedia of Integer Sequences."
Tenenbaum, G. and Mendes-France, M. The Prime Numbers and Their Distribution. Providence, RI: Amer. Math. Soc., p. 22, 2000.
Titchmarsh, E. C. The Theory of the Riemann Zeta Function, 2nd ed. New York: Clarendon Press, 1987.