%I
%S 34,1980,9898
%N Numbers k such that k*7^k + 1 is prime.
%H G. Loeh, <a href="http://guenter.loeh.name/gc/status.html">Generalized Cullen primes</a>
%t Select[Range[3500], PrimeQ[# 7^# + 1] &]
%o (MAGMA) [n: n in [0..3500]  IsPrime(n*7^n+1)];
%o (PARI) is(n)=ispseudoprime(n*7^n+1) \\ _Charles R Greathouse IV_, May 22 2017
%Y Cf. similar sequences listed in A242176.
%K nonn,more,bref
%O 1,1
%A _Vincenzo Librandi_, May 08 2014
%E a(3) from Loeh's list (see Links)  _Bruno Berselli_, May 08 2014
