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.

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A308082 Numbers k such that floor(prime(k)/k) < floor(prime(k+1)/(k+1)).

Original entry on oeis.org

4, 11, 30, 68, 72, 180, 189, 442, 1051, 1059, 2700, 6454, 6458, 6465, 6472, 15927, 40072, 40121, 100361, 100363, 251706, 251709, 251723, 251737, 251761, 637234, 637320, 637323, 637330, 637340, 1617174, 4124436, 4124466, 4124472, 4124705, 10553414
Offset: 1

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Author

Giorgos Kalogeropoulos, May 11 2019

Keywords

Comments

Largest k below 10^8 is 69709965.
If instead of "less than" in floor(prime(k)/k) < floor(prime(k+1)/(k+1)), we use "greater than", we get A283053.

Crossrefs

Cf. A000040, A038605, A283053.

Programs

  • Mathematica
    Select[Range@100000, Floor[Prime@#/#] < Floor[Prime[# + 1]/(# + 1)] &]
  • PARI
    isok(k) = prime(k)\k < prime(k+1)\(k+1); \\ Michel Marcus, May 11 2019
  • PARI
    lista(nn) = {my(p=2, ip=1, q=3); for (n=1, nn, if (p\ip < q\(ip+1), print1(ip, ", ")); p = q; ip ++; q = nextprime(p+1););} \\ Michel Marcus, May 11 2019
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Started in 1964 by Neil J. A. Sloane | Maintained by The OEIS Foundation Inc.

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