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Numbers k such that k*15^k + 1 is prime.
3

%I #19 Sep 08 2022 08:46:08

%S 8,14,44,154,274,694,17426,59430

%N Numbers k such that k*15^k + 1 is prime.

%H G. Loeh, <a href="http://guenter.loeh.name/gc/status.html">Generalized Cullen primes</a>

%t Select[Range[2000], PrimeQ[# 15^# + 1] &]

%o (Magma) [n: n in [0..2500] | IsPrime(n*15^n+1)];

%o (PARI) is(n)=ispseudoprime(n*15^n+1) \\ _Charles R Greathouse IV_, Jun 06 2017

%Y Cf. similar sequences listed in A242176.

%K nonn,more

%O 1,1

%A _Vincenzo Librandi_, May 08 2014

%E a(7)-a(8) from Loeh's list (see Links)