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A109387
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Numbers k such that 3^k - k^3 is prime.
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11
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1, 4, 10, 52, 112, 212, 346, 406, 512, 13904, 76610, 89746, 114892
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OFFSET
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1,2
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COMMENTS
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Terms <= 512 correspond to certified primes. Next term after 13904 is greater than 20000.
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LINKS
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EXAMPLE
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4 is a term 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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PROG
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CROSSREFS
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KEYWORD
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hard,more,nonn
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AUTHOR
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EXTENSIONS
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a(13) from Norbert Schneider submitted by Robert Price, Mar 16 2019
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STATUS
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approved
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