Generalized Ramanujan Primes
Generalized Ramanujan Primes
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广义拉马努金素数
DOI:
10.1007/978-1-4939-1601-6_1
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发表时间:
2011
期刊:
影响因子:
--
通讯作者:
J. Sondow
中科院分区:
文献类型:
--
作者:
Nadine Amersi;Olivia Beckwith;Steven J. Miller;Ryan Ronan;J. Sondow
In 1845, Bertrand conjectured that for all integersx≥ 2, there exists at least one prime in (x∕2,x]. This was proved by Chebyshev in 1860 and then generalized by Ramanujan in 1919. He showed that for anyn≥ 1, there is a (smallest) primeRnsuch thatfor allx≥Rn. In 2009 Sondow calledRnthenth Ramanujan prime and proved the asymptotic behaviorRn∼p2n(wherepmis themth prime). He and Laishram proved the boundsp2n<Rn<p3n, respectively, forn> 1. In the present paper, we generalize the interval of interest by introducing a parameterc∈ (0, 1) and defining thenthc-Ramanujan prime as the smallest integerRc,nsuch that for allx≥Rc,n, there are at leastnprimes in (cx,x]. Using consequences of strengthened versions of the Prime Number Theorem, we prove thatRc,nexists for allnand allc, thatasn→∞, and that the fraction of primes which arec-Ramanujan converges to 1 −c. We then study finer questions related to their distribution among the primes and see that thec-Ramanujan primes display striking behavior, deviating significantly from a probabilistic model based on biased coin flipping. This model is related to the Cramer model, which correctly predicts many properties of primes on large scales but has been shown to fail in some instances on smaller scales.