A103112 Smallest natural number m such that n^n^n - m is a prime.

3, 26, 569, 10978, 106843

Offset: 2

Author

Farideh Firoozbakht, Mar 04 2005

Keywords

• hard
• more
• nonn

Examples

			a(5)=10978 because 5^5^5 - 10978 is a prime and 5^5^5 - k is composite for 0<k<10978.
		

Crossrefs

Cf. A103111, A074967, A074966.

Programs

PARI

a(n)=(x->x-precprime(x))(n^n^n) \\ Charles R Greathouse IV, Nov 25 2014

Extensions

a(6) from Donovan Johnson, Mar 06 2008