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A138578 Numbers n such that 2^(2*n-7)-7 is prime. 0

%I

%S 4,23,361,995,1163,1253

%N Numbers n such that 2^(2*n-7)-7 is prime.

%e 2^(2*23-7)-7=549755813881,

%e 2^(2*361-7)-7=172364133221937103085272756482216056112753534658909761028039668631756215232006\

%e 744379020625060744018369805777923479247838020220755974022884986972234404720831\

%e 691332769255536872593544438018353486799545737272878084128761

%t q=7;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-7)-7) \\ _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 January 24 10:33 EST 2020. Contains 331193 sequences. (Running on oeis4.)