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A054463
Numbers k such that (k+1)^k - k^(k-1) is prime.
1
2, 5, 6, 9, 24, 595
OFFSET
1,1
COMMENTS
a(7) > 3000, if it exists. - Amiram Eldar, Jun 28 2024
MATHEMATICA
Select[Range[1000], PrimeQ[(# + 1)^# - #^(# - 1)] &] (* Vincenzo Librandi, Sep 27 2012 *)
PROG
(PARI) xp1toxp1(n)= { my(y); forstep(x=2, n, 1, y=(x+1)^x - x^(x-1); if(ispseudoprime(y), print1(x, ", "))); }
CROSSREFS
Sequence in context: A122965 A350988 A226810 * A295741 A007503 A337298
KEYWORD
nonn,more
AUTHOR
Cino Hilliard, Aug 30 2003
EXTENSIONS
a(6) from Vincenzo Librandi, Sep 27 2012
STATUS
approved