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.

Showing 1-2 of 2 results.

A228922 Numbers n such that (19^n + 2^n)/21 is prime.

Original entry on oeis.org

5, 13, 41, 43, 83, 139, 557, 863, 1051, 4003
Offset: 1

Views

Author

Robert Price, Sep 08 2013

Keywords

Comments

All terms are primes.
a(11) > 10^5.

Crossrefs

Cf. A057185, A128075, A224507, A225191.

Programs

  • Mathematica
    Select[Prime[Range[1, 100000]], PrimeQ[(19^# + 2^#)/21]&]
  • PARI
    is(n)=ispseudoprime((19^n+2^n)/21) \\ Charles R Greathouse IV, Jun 13 2017

A228225 Numbers n such that (17^n + 3^n)/20 is prime.

Original entry on oeis.org

37, 641, 2521, 7993, 41213
Offset: 1

Views

Author

Robert Price, Aug 16 2013

Keywords

Comments

All terms are primes.
a(6) > 10^5.

Crossrefs

Cf. A128073, A224507, A128075, A227046.

Programs

  • Mathematica
    k=17; Do[ p=Prime[n]; f=(3^p+k^p)/(k+3); If[ PrimeQ[f], Print[p]], {n, 1, 9592} ]
  • PARI
    is(n)=ispseudoprime((17^n+3^n)/20) \\ Charles R Greathouse IV, Jun 13 2017
Showing 1-2 of 2 results.

Started in 1964 by Neil J. A. Sloane | Maintained by The OEIS Foundation Inc.

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