# Brun's constant

> sum of reciprocals of twin primes

**Wikidata**: [Q850251](https://www.wikidata.org/wiki/Q850251)  
**Wikipedia**: [English](https://en.wikipedia.org/wiki/Brun's_constant)  
**Source**: https://4ort.xyz/entity/brun-s-constant


## References

1. Freebase Data Dumps. 2013
2. On-Line Encyclopedia of Integer Sequences
3. [Source](http://books.google.com/books?id=RbEz-_D7sAUC&lpg=PA16&vq=Brun&pg=PA17#v=onepage&q&f=false)