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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
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
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
KEYWORD
nonn
AUTHOR
Michel Planat, Oct 05 2011
STATUS
approved