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A191568
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Numbers k such that k*(k+1)^k+1 is prime.
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1
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OFFSET
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1,2
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COMMENTS
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The corresponding primes are a subset of the generalized Cullen primes (A210339 U A050920). - Jeppe Stig Nielsen, Apr 12 2016
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LINKS
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Table of n, a(n) for n=1..8.
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EXAMPLE
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a(1)=1 because 1*2^1+1=3 is prime, a(2)=2 because 2*3^2+1=19 is prime, a(3)=3 because 3*4^3+1=193 is prime, a(4)=9 because 9*10^9+1=9000000001 is prime, a(5)=10 because 10*11^10+1=259374246011 is prime.
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MATHEMATICA
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Select[Range@ 100, PrimeQ[# (# + 1)^# + 1] &] (* Michael De Vlieger, Apr 12 2016 *)
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PROG
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(PARI) is(n)=ispseudoprime(n*(n+1)^n+1) \\ Charles R Greathouse IV, Jun 13 2017
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CROSSREFS
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Cf. A109618, A110709, A210339, A271718.
Sequence in context: A257026 A057291 A135107 * A279549 A030743 A098020
Adjacent sequences: A191565 A191566 A191567 * A191569 A191570 A191571
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KEYWORD
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nonn,hard,more
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AUTHOR
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Juri-Stepan Gerasimov, Jun 13 2011
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STATUS
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approved
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