A057738 Primes p such that 3^p + 2 is prime.

2, 3, 139

Offset: 1

Author

G. L. Honaker, Jr., Oct 29 2000

Keywords

• more
• nonn
• bref

Comments

Primes in A051783. - Jens Kruse Andersen, Jun 29 2014

No further terms < 1753089 using A051783. - Michael S. Branicky, May 14 2025

Examples

			a(2) = 3 because 3^3 + 2 = 29 is prime.
		

References

• J.-M. De Koninck, Ces nombres qui nous fascinent, Entry 139, p. 48, Ellipses, Paris 2008.

Crossrefs

Cf. A051783, A057739.

Programs

Magma

[p: p in PrimesUpTo(2000) | IsPrime(3^p+2)]; // Vincenzo Librandi, Jun 30 2014

Mathematica

For[n = 1, n < 700, n++, If[PrimeQ[3^Prime[n] + 2], Print[Prime[n]]]] (* Stefan Steinerberger, Mar 18 2006 *)