cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A226473 a(n) is the first prime index where the gap between R(n), Riemann's prime counting function, and Pi(n), the exact prime counting function, is greater than n.

Original entry on oeis.org

109, 556, 1327, 3296, 5380, 10343, 11767, 19202, 19361, 19371, 24121, 42863, 58243, 59453, 59473, 152959, 155809, 155863, 155893, 175594, 175618, 230393, 298545, 298557, 298974, 298986, 299277, 300072, 300135, 302547, 355093, 355111, 463171, 909917, 910219, 993762
Offset: 1

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Author

Jean-François Alcover, Sep 17 2012

Keywords

Examples

			RiemannR(109) = 27.4664... and PrimePi(109) = 29 give the first gap greater than 1, hence a(1) = 109.
		

References

  • H. M. Edwards, Riemann's Zeta Function, Dover Publications, New York, 1974 (ISBN 978-0-486-41740-0), page 35.

Crossrefs

Cf. A057794.

Programs

  • Mathematica
    Reap[For[n = 1; gap = 1, n < 10^6, n++, If[Abs[RiemannR[n] - PrimePi[n]] > gap, Print[{gap, n}]; Sow[n]; gap++]]][[2, 1]]