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Search: id:A109387
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| A109387 |
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Numbers n such that 3^n - n^3 is prime. |
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+0
9
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| 1, 4, 10, 52, 112, 212, 346, 406, 512, 13904, 76610, 89746
(list; graph; listen)
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OFFSET
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1,2
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COMMENT
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Terms <= 512 correspond to certified primes. Next term after 13904 is greater than 20000.
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EXAMPLE
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a(2)=4 because 3^4 -4^3 = 17 is prime
3^10 - 10^3 = 58049 is prime, hence 10 is a term.
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MATHEMATICA
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Do[If[PrimeQ[3^n - n^3], Print[n]], {n, 1, 20000}]
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CROSSREFS
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Adjacent sequences: A109384 A109385 A109386 this_sequence A109388 A109389 A109390
Sequence in context: A099606 A081565 A032495 this_sequence A018844 A007027 A096423
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KEYWORD
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hard,more,nonn
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AUTHOR
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Ryan Propper (rpropper(AT)stanford.edu), Jun 26 2005
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EXTENSIONS
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Two more terms from Donovan Johnson (donovan.johnson(AT)yahoo.com), Feb 26 2008
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