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A242177 Numbers k such that k*7^k + 1 is prime. 3

%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

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Last modified June 2 11:35 EDT 2020. Contains 334771 sequences. (Running on oeis4.)