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A108318 Numbers n such that (n+1)*n^n-1 is prime. 2
2, 3, 4, 5, 7, 11, 15, 26, 52, 116, 359, 1547, 2465 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..13.

EXAMPLE

15 is in the sequence because (15+1)*15^15-1 = 16*15^15-1 = 7006302246093749999, which is prime.

MATHEMATICA

Select[Range[1000], PrimeQ[(# + 1) #^# - 1] &] (* Vincenzo Librandi, Oct 23 2014 *)

PROG

(PARI) isok(n) = isprime((n+1)*n^n-1); \\ Michel Marcus, Oct 23 2014

(MAGMA) [n: n in [1..1000] |IsPrime((n+1)*n^n-1)]; // Vincenzo Librandi, Oct 23 2014

CROSSREFS

Cf. A108879.

Sequence in context: A003037 A259466 A046420 * A006456 A018134 A245823

Adjacent sequences:  A108315 A108316 A108317 * A108319 A108320 A108321

KEYWORD

more,nonn

AUTHOR

Ray G. Opao, Jun 30 2005

STATUS

approved

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Last modified January 26 20:11 EST 2020. Contains 331288 sequences. (Running on oeis4.)