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 A191568 Numbers k such that k*(k+1)^k+1 is prime. 1
 1, 2, 3, 9, 10, 14, 33, 36 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS The corresponding primes are a subset of the generalized Cullen primes (A210339 U A050920). - Jeppe Stig Nielsen, Apr 12 2016 LINKS EXAMPLE 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. MATHEMATICA Select[Range@ 100, PrimeQ[# (# + 1)^# + 1] &] (* Michael De Vlieger, Apr 12 2016 *) PROG (PARI) is(n)=ispseudoprime(n*(n+1)^n+1) \\ Charles R Greathouse IV, Jun 13 2017 CROSSREFS Cf. A109618, A110709, A210339, A271718. Sequence in context: A257026 A057291 A135107 * A279549 A030743 A098020 Adjacent sequences:  A191565 A191566 A191567 * A191569 A191570 A191571 KEYWORD nonn,hard,more AUTHOR Juri-Stepan Gerasimov, Jun 13 2011 STATUS approved

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Last modified May 24 21:08 EDT 2022. Contains 354043 sequences. (Running on oeis4.)