Brun's constant (another Prime Pages' Glossary entries)
 Glossary: Prime Pages: Top 5000: In 1919 Brun showed that the sum of the reciprocals of the twin primes converges to a sum now called Brun's Constant: (1/3 + 1/5) + (1/5 + 1/7) + (1/11 + 1/13) + (1/17 + 1/19) + ... Had this series diverged, then we would have a proof of the twin primes conjecture. But since it convereges, we do not yet know if there are infinitely many twin primes. By calculating the twin primes up to 1014 (and discovering the infamous Pentium bug along the way), Nicely heuristically estimated Brun's constant to be 1.902160578. More recently he has improved this estimate to 1.9021605824 by using the twins to 1.6.1015. See Also: TwinPrime, TwinPrimeConstantRelated pages (outside of this work) The sum of the reciprocals of all primes diverges Twin primes and the Pentium bug Thomas Nicely's homepage with links to some of his workReferences: Nicely95 T. Nicely, "Enumeration to 1014 of the twin primes and Brun's constant," Virginia Journal of Science, 46:3 (1995) 195--204.  MR 97e:11014 (Abstract available) [Available at http://www.trnicely.net/index.html] Chris K. Caldwell © 1999-2018 (all rights reserved)