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.

Previous Showing 21-22 of 22 results.

A224501 Numbers n such that (11^n + 4^n)/15 is prime.

Original entry on oeis.org

7, 53, 67, 71, 443, 26497
Offset: 1

Views

Author

Robert Price, Apr 08 2013

Keywords

Comments

All terms are prime.
a(7) > 10^5.

Crossrefs

Cf. A057178, A128341, A181141, A187819, A217095.

Programs

  • Mathematica
    Select[ Prime[ Range[1, 100000] ], PrimeQ[ (11^# + 4^#)/15 ]& ]
  • PARI
    is(n)=ispseudoprime((11^n+4^n)/15) \\ Charles R Greathouse IV, Jun 06 2017

A225397 Numbers n such that (16^n + 5^n)/21 is prime.

Original entry on oeis.org

31, 109, 373, 409, 619, 823, 1531, 6637, 70687
Offset: 1

Views

Author

Robert Price, Jul 25 2013

Keywords

Comments

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

Crossrefs

Cf. A128340, A128341, A128342, A128343, A227046, A128073.

Programs

  • Mathematica
    k=16; Do[p=Prime[n]; f=(k^p+5^p)/(k+5); If[ PrimeQ[f], Print[p] ], {n, 1, 9592}]
  • PARI
    is(n)=ispseudoprime((16^n+5^n)/21) \\ Charles R Greathouse IV, Jun 13 2017
Previous Showing 21-22 of 22 results.

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

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