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A244916 Primes prime(i) such that prime(i) + 2^(i+1) is also prime. 1
3, 31, 71, 97, 107, 277, 307, 641, 907, 967, 1009, 1447, 3463, 3527, 7757, 8167, 250867, 279047 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..18.

MAPLE

for i from 1 do

        p := ithprime(i) ;

        if isprime(p+2^(i+1)) then

                printf("%d, \n", p) ;

        end if;

end do: # R. J. Mathar, Jul 12 2014

MATHEMATICA

p = 2; lst = {}; While[p < 900000, If[ PrimeQ[ 2^(PrimePi@ p +1) + p], AppendTo[lst, p]; Print@ p]; p = NextPrime@ p]; lst

PROG

(PARI) lista(nn) = {ip = 1; forprime(p=2, nn, if (isprime(2^(ip+1)+p), print1(p, ", ")); ip++; ); } \\ Michel Marcus, Jul 12 2014

CROSSREFS

Cf. A242944, A227126, A228021.

Sequence in context: A133203 A062616 A289733 * A031916 A137185 A243471

Adjacent sequences:  A244913 A244914 A244915 * A244917 A244918 A244919

KEYWORD

nonn,more,hard

AUTHOR

Robert G. Wilson v, Jul 09 2014

STATUS

approved

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Last modified July 31 08:38 EDT 2021. Contains 346369 sequences. (Running on oeis4.)