A088110 Numbers n such that 2^n + n and 2^n - n are noncomposite.

0, 1, 3, 9

Offset: 1

Author

Amarnath Murthy, Sep 25 2003

Keywords

• more
• nonn

Comments

Conjecture: sequence is finite.

No more terms < 88075. - David Wasserman, Jul 20 2005

Examples

			9 is a member as 2^9 + 9 = 521 and 2^9 - 9 = 503 are primes.
		

Crossrefs

Cf. A048744, A052007.

Programs

Magma

[0,1] cat [n: n in [0..1000] | IsPrime(2^n+n) and IsPrime(2^n-n)]; // Vincenzo Librandi, Dec 08 2015

Mathematica

Join[{0, 1}, Select[Range[1000], PrimeQ[2^# + #] && PrimeQ[2^# -#] &]] (* Vincenzo Librandi, Dec 08 2015 *)