A053705 Primes p of form q^k-2 where q is also a prime and k > 1.

2, 7, 23, 47, 79, 167, 241, 359, 727, 839, 1367, 1847, 2207, 2399, 3719, 5039, 6857, 7919, 10607, 11447, 14639, 16127, 17159, 19319, 19681, 28559, 29789, 29927, 36479, 44519, 49727, 50651, 54287, 57119, 66047, 85847, 97967, 113567, 128879

Offset

1,1

Links

Amiram Eldar, Table of n, a(n) for n = 1..10000

Example

79 = 3^4-2.
241 = 3^5-2.

Mathematica

Do[s=2+Prime[n]; If[Equal[Length[FactorInteger[s]], 1]&&!PrimeQ[s], Print[s-2]], {n, 1, 100000}]
fQ[n_] := PrimeNu[n + 2] == 1 && ! PrimeQ[n + 2]; Select[ Prime@ Range@ 15000, fQ] (* Robert G. Wilson v, Apr 01 2012 *)

Prog

(PARI) lista(nn) = forprime (p=1, nn, if (ispower(p+2, , &q) && isprime(q), print1(p, ", ")); ); \\ Michel Marcus, Dec 11 2014

Crossrefs

Cf. A025475. Subsequence of A053705.

Sequence in context: A049572 A094786 A028871 * A247175 A049001 A049002

Adjacent sequences: A053702 A053703 A053704 * A053706 A053707 A053708

Keyword

nonn,changed

Author

Labos Elemer, Feb 14 2000

Extensions

Definition corrected by Zak Seidov, Dec 11 2014

Status

approved