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A054463 Numbers n such that (n+1)^n - n^(n-1) is prime. 1
2, 5, 6, 9, 24, 595 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

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)= { sr=0; forstep(x=2, n, 1, y=(x+1)^x - x^(x-1); if(ispseudoprime(y), print(x" "y" "); sr+= 1.0/y; ) ); print(); print(sr) }

CROSSREFS

Sequence in context: A051677 A122965 A226810 * A295741 A007503 A184418

Adjacent sequences:  A054460 A054461 A054462 * A054464 A054465 A054466

KEYWORD

nonn

AUTHOR

Cino Hilliard, Aug 30 2003

EXTENSIONS

a(6) from Vincenzo Librandi, Sep 27 2012

STATUS

approved

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Last modified October 22 08:00 EDT 2019. Contains 328315 sequences. (Running on oeis4.)