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 A196671 The number of Chebyshev primes (of index 1) less than 10^n, (n=1,2,...). 0
 0, 0, 42, 516, 4498, 414123 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,3 COMMENTS The Chebyshev primes (of index 1) are such odd primes that satisfy li[psi(p)]-li[psi(p-1)]<1 (sequence A196667), where li(x) is the logarithmic integral and psi(x) is the Chebyshev's psi function. The present sequence lists the number of Chebyshev primes less than 10^n, (n=1,2,...). The sequence suggests the density pi(x)/2 for the Chebyshev primes, where pi(x) is the density of primes. LINKS Table of n, a(n) for n=1..6. M. Planat and P. Solé, Efficient prime counting and the Chebyshev primes arXiv:1109.6489 [math.NT] CROSSREFS Cf. A196667. Sequence in context: A273223 A163727 A160065 * A248448 A248449 A245874 Adjacent sequences: A196668 A196669 A196670 * A196672 A196673 A196674 KEYWORD nonn AUTHOR Michel Planat, Oct 05 2011 STATUS approved

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Last modified December 10 12:10 EST 2023. Contains 367710 sequences. (Running on oeis4.)