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A128944 Numbers n such that the smallest prime > 2^n is a twin prime member. 1

%I #8 Mar 07 2023 11:22:31

%S 1,2,3,4,9,10,16,23,229,245,266,338,628,4118

%N Numbers n such that the smallest prime > 2^n is a twin prime member.

%F A014210(a(n)) = A128949(n).

%e For n=4, 17 is the smallest prime > 2^4 and is a member of the twin prime pair 17, 19.

%t Select[Range[4200],AnyTrue[NextPrime[2^#]+{2,-2},PrimeQ]&] (* _Harvey P. Dale_, Mar 07 2023 *)

%o (PARI) g(n,b)=for(x=1,n,y=nextprime(b^x);if(ispseudoprime(y+2),print1(x",")))

%K hard,more,nonn

%O 1,2

%A _Cino Hilliard_, Apr 28 2007

%E Edited by _Ray Chandler_, May 12 2007

%E One more term from _Ryan Propper_, Jan 03 2008

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Last modified April 18 22:18 EDT 2024. Contains 371782 sequences. (Running on oeis4.)