A134985 Numbers k such that (k-1)^(k+1) - k^k is prime.

5, 6, 7, 13, 17, 171, 174, 378, 17641

Offset: 1

Author

Carl R. White, Feb 05 2008

Keywords

• hard
• more
• nonn

Comments

No more terms up to 10000. - Rick L. Shepherd, May 16 2008

Examples

			12^14 - 13^13 = 981043357956611, which is prime, so 13 is in the list.
		

Programs

Mathematica

Select[Table[n,{n,5,400}],PrimeQ[(#-1)^(#+1)-#^#]&] (* Vladimir Joseph Stephan Orlovsky, Mar 03 2011*)

Extensions

a(9) from Michael S. Branicky, Sep 05 2024