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%I #23 Nov 20 2021 11:36:35
%S 3,7,13,3121,31,43,549755813881,73,991,1321,248821,157,2731,211,241,
%T 34271896307617,307,6841,13107199999999999999981,421,463,
%U 141050039560662968926081,331753,601,17551,7625597484961,757,1816075630094014572464024421543167816955354437761
%N Smallest prime of the form n^k-(n-1) or 0 if no such prime exists.
%C All values up to n=70 have been found and proved to be primes. n=71 has k=3019 and gives a probable prime.
%C See A113516, which gives the k values and is the main entry for these primes, for more extensively researched information. - _Peter Munn_, Nov 20 2021
%H Blake Branstool, <a href="/A343589/b343589.txt">Table of n, a(n) for n = 2..70</a>
%e For n=2 and k=2, 2^2-(2-1)=3 thus a(2)=3. k is 2 as well for n=3,4.
%e For n=5 the first k to result in a prime is 5, 5^5-(5-1)=3121 thus a(5)=3121.
%o (PARI) a(n) = my(k=1, p); while (!isprime(p=n^k-(n-1)), k++); p; \\ _Michel Marcus_, Nov 17 2021
%Y A113516 gives the k values.
%Y Cf. A076846, A084741, A084745, A346154.
%K nonn
%O 2,1
%A _Blake Branstool_, Apr 20 2021
%E Name revised by _Peter Munn_, Nov 16 2021