login
A269227
Numbers n such that 7^n + 6^(n + 1) is prime.
0
0, 1, 4, 5, 12, 16, 27, 87, 252, 1052, 1691, 3237, 3669, 16140, 17072, 27932, 70811
OFFSET
1,3
COMMENTS
a(18) > 10^5.
MATHEMATICA
Select[Range[0, 100000], PrimeQ[7^# + 6^(# + 1)] &]
PROG
(Magma) [n: n in [0..500] | IsPrime(7^n+6^(n+1))]; // Vincenzo Librandi, Jul 12 2016
(PARI) is(n)=ispseudoprime(7^n+6^(n+1)) \\ Charles R Greathouse IV, Jun 13 2017
CROSSREFS
Cf. A093765.
Sequence in context: A137619 A115375 A212114 * A103650 A131116 A352215
KEYWORD
nonn,more
AUTHOR
Robert Price, Jul 11 2016
STATUS
approved