A244913 Primes p such that 2^pi(p-1) - p is also prime.

11, 13, 17, 19, 23, 37, 61, 233, 257, 1553, 2879, 4919, 6389, 7621, 8081, 35593, 37951, 96263, 206419, 596803, 1202837

Offset

1,1

Comments

a(22) > 1211303. - J.W.L. (Jan) Eerland, Dec 08 2022

Links

Table of n, a(n) for n=1..21.

Formula

{p in A000040: 2^[A000720(p-1)]-p in A000040}. - R. J. Mathar, Jul 11 2014

Maple

for i from 1 do
    p := ithprime(i) ;
    if isprime(2^(numtheory[pi](p-1))-p) then
        printf("%d, \n", p) ;
    end if;
end do: # R. J. Mathar, Jul 11 2014

Mathematica

p = 2; lst = {}; While[p < 800001, If[ PrimeQ[ 2^(PrimePi@ p-1) - p], AppendTo[lst, p]; Print@ p]; p = NextPrime@ p]; lst
n=1; Monitor[Parallelize[While[True, If[PrimeQ[2^(PrimePi[Prime[n]-1])-Prime[n]], Print[Prime[n]]]; n++]; n], n] (* J.W.L. (Jan) Eerland, Dec 08 2022 *)

Prog

(PARI) is(n)=isprime(n) && isprime(2^primepi(n-1)-n) \\ Charles R Greathouse IV, Feb 25 2017

Crossrefs

Cf. A078686, A227126.

Sequence in context: A050719 A217062 A293662 * A098415 A329176 A067283

Adjacent sequences: A244910 A244911 A244912 * A244914 A244915 A244916

Keyword

nonn,more

Author

Robert G. Wilson v, Jul 09 2014

Extensions

a(21) from J.W.L. (Jan) Eerland, Dec 08 2022

Status

approved