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 A118664 Least prime p such that n*(p#^2)-1 is prime or 0 if n is a square so no prime possible. 0

%I

%S 2,2,2,0,2,2,3,2,0,3,2,2,3,3,2,0,2,2,3,2,2,269,3,3,0,2,2,7,5,29,11,2,

%T 2,3,2,0,11,2,5,3,2,2,5,3,2,5,5,2,0,2,17,3,2,11,3,2,2,3,7,2,7,5,2,0,3,

%U 2,3,2,5,7,2,3,5,3,3,5,2,2,3,3,0,41,2,3,7,7,2,3,3,2,5,2,3,53,2,2,3,3,7,0

%N Least prime p such that n*(p#^2)-1 is prime or 0 if n is a square so no prime possible.

%e 1*(2^2)-1=3 prime so a(1)=2

%e 7*(2^2)-1=27 composite

%e 7*((2*3)^2)-1=251 prime so a(7)=3

%K nonn

%O 1,1

%A _Pierre CAMI_, May 19 2006

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Last modified November 24 03:39 EST 2020. Contains 338607 sequences. (Running on oeis4.)