A098463 Numbers k such that A055869(k) = (k+1)^k - k^k is prime.

2, 3, 5, 7, 167

Offset: 1

Author

Hugo Pfoertner, Sep 14 2004

Keywords

• nonn
• hard
• more

Comments

The next term is > 5000.

Examples

			a(2) = 3 because (3+1)^3 - 3^3 = 4^3 - 3^3 = 64 - 27 = 37 is prime.
		

Crossrefs

Cf. A055869 ((n+1)^n-n^n), A085682 (k^k-(k-1)^k is prime).

Programs

Magma

[n: n in [0..190]| IsPrime((n+1)^n -n^n)]; // Vincenzo Librandi, Jun 22 2014

Mathematica

Select[Range[300], PrimeQ[(#+1)^#-#^#]&] (* Vladimir Joseph Stephan Orlovsky, Mar 03 2011 *)

PARI

isok(k) = ispseudoprime((k+1)^k - k^k); \\ Jinyuan Wang, Mar 19 2020