Prime p such that 2^p + 21 is also prime.

A175235

Prime p such that 2^p + 21 is also prime.

Terms

    a(0) =3a(1) =5a(2) =7a(3) =11a(4) =19a(5) =61a(6) =163a(7) =911a(8) =997a(9) =16657a(10) =36551

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