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%I #7 Apr 08 2018 16:04:18
%S 16,17,19,21,22,24,25,33,34,36,46,49,60,70,90,93,112,137,143,207,216,
%T 263,280,477,647,1257,1383
%N Numbers n such that 2^(2*n-31)-31 is prime.
%e 2^(2*19-31)-31=97, 2^(2*21-31)-31=2017, 2^(2*22-31)-31=8161, ...
%t q=31;For[i=q,i<=q,a={};Do[x=2^(2*n-i)-i;If[PrimeQ[x],AppendTo[a,n]],{n,20^2}];Print["2^(2*n-",i,")-",i," ",a];i=i+2]
%t Select[Range[1500],PrimeQ[2^(2#-31)-31]&]
%o (PARI) is(n)=isprime(2^(2*n-31)-31) \\ _Charles R Greathouse IV_, Jun 13 2017
%K nonn,easy
%O 1,1
%A _Vladimir Joseph Stephan Orlovsky_, May 13 2008
%E More terms from _Harvey P. Dale_, Apr 08 2018
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