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%I #15 Jun 01 2019 09:36:40
%S 3,2,3,2,2,3,3,19,2,2,45,7,15,7,5,5,44,2,4,3,84,62,128,5,4,90,16,37,
%T 15,11,311,15,295,72,3,3,242,2,126,64,152,11,78,26,2,13,14,26,140,2,
%U 24,16,157,4,49,13,2,123,64,16,61,206,6,76,412,31,84,23,24,9,471,26,422,227,8
%N a(n) = least k such that k^n*(k^n-1)-1 is prime.
%C Under the Bunyakovsky conjecture, a(n) exists for every n. [_Charles R Greathouse IV_, Dec 27 2011]
%H Pierre CAMI, <a href="/A101406/b101406.txt">Table of n, a(n) for n = 1..700</a>
%e 2^5*(2^5-1) - 1 = 32*31 - 1 = 991 (prime) so for n=5 a(5)=2.
%t a = {}; Do[ k = 1; While[c = k^n; t = c*(c - 1) - 1; ! PrimeQ[t], k++ ]; AppendTo[a, k];, {n, 75}]; a (* _Ray Chandler_, Jan 27 2005 *)
%Y Cf. A101446.
%K nonn
%O 1,1
%A _Pierre CAMI_, Jan 24 2005
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