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Search: id:A117706
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| A117706 |
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Numbers n such that 6^n-n^6 is prime. |
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+0
8
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OFFSET
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1,2
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COMMENT
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a(9) found by Donovan Johnson
Comment by Donovan Johnson : A117705 and A117706 are both Fermat probable prime to four bases. They have also passed a Miller-Rabin primality test in five randomly chosen bases. checked the n values up to 70000 for A117705 and n values up to 60000 for A117706. No additional primes or probable primes were found.
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EXAMPLE
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a(2)=7 because 6^7 - 7^6 = 162287 is prime
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MATHEMATICA
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Do[If[PrimeQ[(6^n-n^6)], Print[n]], {n, 1, 3000}]
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CROSSREFS
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Sequence in context: A060983 A001001 A067692 this_sequence A066673 A088985 A022005
Adjacent sequences: A117703 A117704 A117705 this_sequence A117707 A117708 A117709
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KEYWORD
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hard,more,nonn
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AUTHOR
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Mohammed Bouayoun (Mohammed.Bouayoun(AT)sanef.com), Apr 13 2006, Jan 08 2008
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