A253380 Numbers k such that 17^k + 4 is prime.
0, 2, 6, 18, 7238
Offset: 1
Examples
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.
Crossrefs
Programs
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Mathematica
Select[Range@10^5, PrimeQ[17^# + 4] &] (* Michael De Vlieger, Jan 03 2015 *)
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PARI
for(n=0, 1e5, if(ispseudoprime(17^n+4), print1(n, ", ")))
Comments