Mertens Function Calculator

M(n) = Σμ(k)

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About Mertens Function Calculator

A Mertens function calculator computing M(n) = Σ_{k=1}^{n} μ(k). The Mertens conjecture (|M(n)| < √n) is FALSE — disproved by Odlyzko & te Riele (1985). But RH ⟺ M(n) = O(n^{1/2+ε}). Shows cumulative values and growth. Client-side.

Mertens Function Calculator Features

  • M(n) computation
  • μ(k) values
  • Conjecture
  • RH connection
  • Graph
Mertens function M(n) = Σμ(k) = μ(1)+μ(2)+...+μ(n). M(1)=1, M(2)=0, M(3)=−1, M(4)=−1, M(5)=−2... The Mertens conjecture (|M(n)|<√n for all n>1) was disproved in 1985, but the first counterexample is > 10^{10^{13}}!

How to Use

Enter n:

  • M(n): Cumulative sum
  • μ(k): Individual values
  • √n bound: Mertens comparison

The Disproof

Mertens conjectured |M(n)|<√n (1897). Odlyzko & te Riele (1985) disproved it — but the first counterexample hasn't been found explicitly! Only its existence is proven. The actual violation occurs at an astronomically large n.

Riemann Connection

RH ⟺ M(n) = O(n^{1/2+ε}) for all ε>0. So M(n) grows at most like n^{0.5+tiny}. If M(n) could be bounded by n^{0.5−δ} for some δ>0, that would prove more than RH!

Step-by-Step Instructions

  1. 1Enter n.
  2. 2Compute M(n).
  3. 3See μ values.
  4. 4Compare √n.
  5. 5Check growth.

Mertens Function Calculator — Frequently Asked Questions

How was Mertens' conjecture disproved?+

Odlyzko & te Riele (1985) used the relation between M(n) and zeros of ζ(s). They showed that lim sup M(n)/√n > 1.06 and lim inf M(n)/√n < −1.009. But the actual first n where |M(n)|>√n is beyond computation — estimated around 10^{10^{13}}.

What IS M(n) measuring?+

M(n) measures the 'excess' of squarefree numbers with an even number of prime factors over those with an odd number, among 1..n. When M(n)>0: more even-factored squarefree numbers. When M(n)<0: more odd-factored.

Can M(n) be efficiently computed for large n?+

Yes! Using the Deleglise-Rivat algorithm, M(n) can be computed in O(n^{2/3}) time and O(n^{1/3}) space. This is based on the identity M(n) = 1 - Σ_{k=2}^{n} M(⌊n/k⌋) with block optimization.

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