A243397 -id:A243397 - cp's OEIS frontend

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

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

Offset: 1

Felix Fröhlich, Dec 01 2014

No further terms up to 10000.

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

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

[n: n in [0..300] | IsPrime(15^n+4)]; // Vincenzo Librandi, Dec 01 2015

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

for(n=0, 1e5, if(ispseudoprime(15^n+4), print1(n, ", ")))

Offset changed to 1 by Georg Fischer, Sep 26 2022

A253380 Numbers k such that 17^k + 4 is prime.

Original entry on oeis.org

0, 2, 6, 18, 7238

Offset: 1

Felix Fröhlich, Dec 31 2014

No further terms up to 10000.

No further terms up to 37200. - Michael S. Branicky, Mar 22 2023

			For k = 0: 17^0 + 4 = 5, which is prime, so 0 is a term of the sequence.
For k = 2: 17^2 + 4 = 293, which is prime, so 2 is a term of the sequence.

Corresponding sequences for k^n+4: A058958 (k=3), A124621 (k=5), A096305(k=7), A217384 (k=9), A137236 (k=13), A247166 (k=15), A243397 (k=19).

Select[Range@10^5, PrimeQ[17^# + 4] &] (* Michael De Vlieger, Jan 03 2015 *)

for(n=0, 1e5, if(ispseudoprime(17^n+4), print1(n, ", ")))

cp's OEIS Frontend

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

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