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A084898
Numbers k such that k^k*k! + 1 is prime.
0
1, 3, 7, 13, 23, 55, 90, 337, 2313, 8767
OFFSET
1,2
COMMENTS
All terms under 500 correspond to certified primes (Primo 2.2.0 beta). a(10) > 2500. - Ryan Propper, Apr 05 2006
a(11) > 10000. - Eric Snyder, Jun 03 2022
EXAMPLE
7 is in the sequence because 7^7*7! + 1 = 4150656721 is prime.
MATHEMATICA
Do[If[PrimeQ[n^n*n!+1], Print[n]], {n, 600}]
CROSSREFS
Sequence in context: A100720 A297852 A297953 * A147380 A146606 A101302
KEYWORD
more,nonn
AUTHOR
Farideh Firoozbakht, Jul 14 2003
EXTENSIONS
a(9) from Ryan Propper, Apr 05 2006
a(10) from Eric Snyder, Jun 03 2022
STATUS
approved