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A138579 Numbers n such that 2^(2*n-9)-9 is prime. 0

%I

%S 5,7,9,10,13,15,21,67,75,126,130,147,165,273,286,354,369

%N Numbers n such that 2^(2*n-9)-9 is prime.

%e 2^(2*7-9)-9=23, 2^(2*9-9)-9=503, 2^(2*10-9)-9=2039, 2^(2*13-9)-9=131063

%t q=9;For[i=q,i<=q,a={};Do[x=2^(2*n-i)-i;If[PrimeQ[x],AppendTo[a,n]],{n,10^2}];Print["2^(2*n-",i,")-",i," ",a];i=i+2]

%o (PARI) is(n)=isprime(2^(2*n-9)-9) \\ _Charles R Greathouse IV_, Jun 13 2017

%K nonn,easy

%O 1,1

%A _Vladimir Joseph Stephan Orlovsky_, May 13 2008

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Last modified August 11 03:41 EDT 2022. Contains 356046 sequences. (Running on oeis4.)