A247166 Numbers k such that 15^k+4 is prime.

0, 1, 2, 7, 10, 39, 42, 201, 225, 551

Offset

1,3

Comments

No further terms up to 10000.

No further terms up to 10^5. - Tyler NeSmith, Jan 21 2021

Links

Table of n, a(n) for n=1..10.

Mathematica

a247166[n_Integer] := Select[Range[n], PrimeQ[15^# + 4] &]; a247166[10^4] (* Michael De Vlieger, Dec 03 2014 *)

Prog

(PARI) for(n=0, 1e5, if(ispseudoprime(15^n+4), print1(n, ", ")))
(Magma) [n: n in [0..300] | IsPrime(15^n+4)]; // Vincenzo Librandi, Dec 01 2015

Crossrefs

Corresponding sequences for m^k+4: A058958 (m=3), A124621 (m=5), A096305 (m=7), A217384 (m=9), A137236 (m=13), A243397 (m=19).

Sequence in context: A056656 A351240 A151346 * A110739 A179117 A133154

Adjacent sequences: A247163 A247164 A247165 * A247167 A247168 A247169

Keyword

nonn,more

Author

Felix Fröhlich, Dec 01 2014

Extensions

Offset changed to 1 by Georg Fischer, Sep 26 2022

Status

approved