A191717 - OEIS

A191717

Numbers n such that n*(n-1)^n-(n-1)*n^(n-1)+1 is prime.

3, 5, 18, 23, 78, 131, 177

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OFFSET

1,1

LINKS

EXAMPLE

a(1)=3 because 3*2^3-2*3^2+1=7 is prime, a(2)=5 because 5*4^5-4*5^4+1=2621 is prime.

PROG

(PARI) is(n)=ispseudoprime(n*(n-1)^n-(n-1)*n^(n-1)+1) \\ Charles R Greathouse IV, Jun 13 2017

CROSSREFS

KEYWORD

nonn,hard

AUTHOR

STATUS

approved