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A193177
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Numbers n such that 2*17^n - 1 is prime.
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1
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OFFSET
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1,1
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COMMENTS
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Is it true that a(n)= 0 or 2 (mod 6) and a(n)= 0 or 2 (mod 4)?
Yes. This can be proved mod 21. [Charles R Greathouse IV, Jul 31 2011]
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LINKS
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Table of n, a(n) for n=1..7.
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MATHEMATICA
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Table[If[PrimeQ[2*17^m-1], m], {m, 1, 2000}]//Union
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PROG
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(PARI) forstep(n=2, 1e4, [4, 2], if(ispseudoprime(2*17^n-1), print1(n", "))) \\ Charles R Greathouse IV, Jul 31 2011
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CROSSREFS
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Sequence in context: A244379 A189100 A085637 * A157870 A285991 A078838
Adjacent sequences: A193174 A193175 A193176 * A193178 A193179 A193180
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KEYWORD
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nonn
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AUTHOR
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José María Grau Ribas, Jul 17 2011
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STATUS
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approved
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