• Corpus ID: 7077803

Ramanujan Primes: Bounds, Runs, Twins, and Gaps

  title={Ramanujan Primes: Bounds, Runs, Twins, and Gaps},
  author={Jonathan Sondow and John W. Nicholson and Tony D. Noe},
  journal={arXiv: Number Theory},
The $n$th Ramanujan prime is the smallest positive integer $R_n$ such that if $x \ge R_n$, then the interval $(x/2,x]$ contains at least $n$ primes. We sharpen Laishram's theorem that $R_n < p_{3n}$ by proving that the maximum of $R_n/p_{3n}$ is $R_5/p_{15} = 41/47$. We give statistics on the length of the longest run of Ramanujan primes among all primes $p<10^n$, for $n\le9$. We prove that if an upper twin prime is Ramanujan, then so is the lower; a table gives the number of twin primes below… 

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Mathematics Subject Classification: Primary 11A41. Keywords: prime gap, Ramanujan prime