A054463 Numbers k such that (k+1)^k - k^(k-1) is prime.

2, 5, 6, 9, 24, 595

Offset

1,1

Comments

a(7) > 3000, if it exists. - Amiram Eldar, Jun 28 2024

Links

Table of n, a(n) for n=1..6.

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

Adjacent sequences: A054460 A054461 A054462 * A054464 A054465 A054466

Keyword

nonn,more

Author

Cino Hilliard, Aug 30 2003

Extensions

a(6) from Vincenzo Librandi, Sep 27 2012

Status

approved