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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A287061 Numbers k such that (10^(k+3)*6319 + 863)/9 is prime (k > 0).

Original entry on oeis.org

11, 19, 23, 31, 73, 257, 613, 5327, 62359
Offset: 1

Views

Author

Mikk Heidemaa, May 19 2017

Keywords

Comments

The generated prime numbers are of the form '702'||...'1'...||'207' ('1' concatenated k times to which the prefix '702' and the suffix '207' are concatenated once).
a(1)..a(7) themselves are primes. a(10) > 80000, if it exists.

Examples

			11 is a term as (10^(11+3)*6319 + 863)/9 = 70211111111111207 is prime.
23 is a term because (10^(23+3)*6319 + 863)/9 = 70211111111111111111111111207 is prime.

Crossrefs

Cf. A032674, A260405, A286916.

Programs

  • Mathematica
    ParallelMap[ If[ PrimeQ[ (10^(#+3)*6319+863)/9], #, Nothing]&, Range[1000]]
  • PARI
    is(n) = ispseudoprime((10^(n+3)*6319+863)/9); \\ Altug Alkan, Jul 23 2017
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Started in 1964 by Neil J. A. Sloane | Maintained by The OEIS Foundation Inc.

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