Number of Primes between two integers

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Discussion Overview

The discussion centers on the quest for a formula that can calculate the exact number of prime numbers between two given integers. Participants explore the distinction between formulas and algorithms in this context, particularly in relation to known functions like pi(n) and the Prime Number Theorem.

Discussion Character

  • Exploratory, Debate/contested, Mathematical reasoning

Main Points Raised

  • One participant inquires about the existence of a formula that provides the exact number of primes between two integers, expressing frustration with existing methods that require prior knowledge of primes.
  • Another participant asserts that no exact formula exists, but suggests that as the integers approach infinity, the distribution of primes aligns with the Prime Number Theorem.
  • A different participant proposes that the prime counting function pi(n) could be used to construct a formula for the number of primes between two integers, but acknowledges that this might be considered an algorithm rather than a straightforward formula.
  • The original poster expresses a desire for a formula that elucidates the distribution of primes without relying on prior knowledge of primes or algorithms.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the existence of a formula for the exact number of primes between two integers. There are competing views regarding the use of pi(n) and the distinction between formulas and algorithms.

Contextual Notes

The discussion highlights the limitations in defining what constitutes a formula versus an algorithm in the context of prime counting, as well as the challenges in achieving exact counts without prior knowledge of primes.

Cheung
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Is there a formula to calculate the EXACT number of primes between two integers? There are many very good ways of ESTIMATING the number but I have found very few that give the EXACT number, and those that do essentially require the knowledge of primes before hand (Legendre and Miessel.) While those are all nice I am looking for a formula (not an algorithm) that will spit out the EXACT number of primes by knowing only the two boundaries. Has it been done?
 
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Exact? No. But as the numbers in question approach infinity, they behave more accordingly to the Prime Number Theorem.
 
Thank you both for your reply's and to jbriggs444 I would consider using the logarithmic pi(x) an algorithm. I am looking for a formula/ function that would shed more light on the distribution of primes by solving for the number of primes using only the two integer limits.
 

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