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A247166
Numbers k such that 15^k+4 is prime.
2
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
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
KEYWORD
nonn,more
AUTHOR
Felix Fröhlich, Dec 01 2014
EXTENSIONS
Offset changed to 1 by Georg Fischer, Sep 26 2022
STATUS
approved