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Liouville Summatory Function


LiouvilleL

The Liouville summatory function is the summatory function

 L(n)=sum_(k=1)^nlambda(k),
(1)

where n is a positive integer and lambda(k) is the Liouville function. For real numbers x>=0, define L(x)=L(|_x_|), with L(0)=0, where |_x_| is the floor function. Its first values for n=1, 2, ... are 1, 0, -1, 0, -1, 0, -1, -2, -1, 0, -1, -2, -3, -2, -1, 0, -1, -2, -3, -4, ... (OEIS A002819).

Lehman (1960) gives the following formulas (see also Borwein et al. 2008).

 L(x)=sum_(m=1)^(x/w)mu(m){|_sqrt(x/m)_|-sum_(1<=k<v)lambda(k)(|_x/(km)_|-|_x/(mv)_|)}
-sum_(x/w<l<=x/v)L(x/l)sum_(m|l; m=1)^(x/w)mu(m)
(2)

and

 L(x)=sum_(k=1)^gM(x/(k^2))+sum_(l=1)^(x/g^2)mu(l)|_sqrt(x/l)_|-gM(x/(g^2)),
(3)

where k, l, and m range over the positive integers, mu(n) is the Möbius function, M(x) is the Mertens function, and v, w, and x are positive real numbers with v<w<x. The second formula holds for any positive integer g.

The refuted Pólya conjecture asserted that L(n)<=0 for all n>=2. In this range, the first positive value occurs at n=906150257 (Tanaka 1980). The first zeros are 2, 4, 6, 10, 16, 26, 40, 96, 586, 906150256, 906150294, 906150308, 906150310, 906150314, 906151516, ... (OEIS A028488). The function L(x) changes sign infinitely often (Borwein et al. 2008).

The values of L(10^n) for n=0, 1, 2, ... are 1, 0, -2, -14, -94, -288, -530, -842, -3884, ... (OEIS A090410).


See also

Liouville Function, Mertens Function, Pólya Conjecture, Summatory Function

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References

Borwein, P.; Ferguson, R.; and Mossinghoff, M. J. "Sign Changes in Sums of the Liouville Function." Math. Comput. 77, 1681-1694, 2008. https://doi.org/10.1090/S0025-5718-08-02036-X.Fawaz, A. Y. "The Explicit Formula for L_0(x)." Proc. London Math. Soc. 1, 86-103, 1951.Gupta, H. "On a Table of Values of L(n)." Proc. Indian Acad. Sci. Sec. A 12, 407-409, 1940.Gupta, H. "A Table of Values of Liouville's Function L(n)." Res. Bull. East Panjab University, No. 3, 45-55, 1950.Lehman, R. S. "On Liouville's Function." Math. Comput. 14, 311-320, 1960.Ramanujan, S. "Irregular Numbers." J. Indian Math. Soc. 5, 105-106, 1913.Ramanujan, S. Collected Papers of Srinivasa Ramanujan (Ed. G. H. Hardy, P. V. S. Aiyar, and B. M. Wilson). Providence, RI: Amer. Math. Soc., pp. 20-21, 2000.Ribenboim, P. Algebraic Numbers. New York: Wiley, p. 44, 1972.Roberts, J. The Lure of the Integers. Washington, DC: Math. Assoc. Amer., p. 279, 1992.Sloane, N. J. A. Sequences A002819/M0042, A028488, and A090410 in "The On-Line Encyclopedia of Integer Sequences."Tanaka, M. "A Numerical Investigation on Cumulative Sum of the Liouville Function." Tokyo J. Math. 3, 187-189, 1980.

Cite this as:

Weisstein, Eric W. "Liouville Summatory Function." From MathWorld--A Wolfram Resource. https://mathworld.wolfram.com/LiouvilleSummatoryFunction.html

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