A217130 Numbers n such that 7^n + 6 is prime.

0, 1, 3, 16, 36, 244, 315, 2577, 9500, 17596, 25551, 32193, 32835, 36504, 75136

Offset: 1

Author

Vincenzo Librandi, Oct 01 2012

Keywords

• nonn

Comments

a(16) > 10^5. - Robert Price, Jan 24 2014

Crossrefs

Cf. A236371, A217131, A191469, A090669, A096305, A217130, A217132, A152213.

Programs

Magma

/* The code produces the sequence up to 315: */ [n: n in [0..2000] | IsPrime(7^n+6)];

Mathematica

Select[Range[0, 5000], PrimeQ[7^# + 6] &]

PARI

for(n=1, 5000, if(isprime(7^n+6), print1(n", ")))

Extensions

a(9)-a(15) from Robert Price, Jan 24 2014