A242177 Numbers k such that k*7^k + 1 is prime.

34, 1980, 9898

Offset: 1

Author

Vincenzo Librandi, May 08 2014

Keywords

• nonn
• more
• bref

Links

• G. Loeh, Generalized Cullen primes

Crossrefs

Cf. similar sequences listed in A242176.

Programs

Magma

[n: n in [0..3500] | IsPrime(n*7^n+1)];

Mathematica

Select[Range[3500], PrimeQ[# 7^# + 1] &]

PARI

is(n)=ispseudoprime(n*7^n+1) \\ Charles R Greathouse IV, May 22 2017

Extensions

a(3) from Loeh's list (see Links) - Bruno Berselli, May 08 2014