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A098463
Numbers k such that A055869(k) = (k+1)^k - k^k is prime.
3
2, 3, 5, 7, 167
OFFSET
1,1
COMMENTS
The next term is > 5000.
EXAMPLE
a(2) = 3 because (3+1)^3 - 3^3 = 4^3 - 3^3 = 64 - 27 = 37 is prime.
MATHEMATICA
Select[Range[300], PrimeQ[(#+1)^#-#^#]&] (* Vladimir Joseph Stephan Orlovsky, Mar 03 2011 *)
PROG
(Magma) [n: n in [0..190]| IsPrime((n+1)^n -n^n)]; // Vincenzo Librandi, Jun 22 2014
(PARI) isok(k) = ispseudoprime((k+1)^k - k^k); \\ Jinyuan Wang, Mar 19 2020
CROSSREFS
Cf. A055869 ((n+1)^n-n^n), A085682 (k^k-(k-1)^k is prime).
Sequence in context: A075048 A281021 A230046 * A064155 A230047 A230042
KEYWORD
nonn,hard,more
AUTHOR
Hugo Pfoertner, Sep 14 2004
STATUS
approved