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A156982
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Numbers k such that 2^k + 29 is prime.
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7
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1, 3, 5, 7, 9, 13, 15, 17, 23, 27, 33, 37, 43, 63, 69, 73, 79, 89, 117, 127, 239, 395, 409, 465, 837, 2543, 10465, 10837, 17005, 19285, 24749, 26473, 29879, 49197, 56673, 67119, 67689, 71007, 109393, 156403, 158757, 181913, 190945, 207865, 222943, 419637
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OFFSET
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1,2
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COMMENTS
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n cannot be of the form 4m+2 or 4m because 2^(2m+2) + 29 is divisible by 3 and 2^4m + 29 is divisible by 15. - Avik Roy (avik_3.1416(AT)yahoo.co.in), Feb 21 2009
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LINKS
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EXAMPLE
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For k = 1, 2^1 + 29 = 31.
For k = 3, 2^3 + 29 = 37.
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MATHEMATICA
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Delete[Union[Table[If[PrimeQ[2^n + 29], n, 0], {n, 1, 2600}]], 1]
Select[Range[500000], PrimeQ[2^#+29]&] (* Robert Price, Oct 04 2015 *)
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PROG
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CROSSREFS
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Cf. A019434 (Fermat primes 2^(2^n)+1).
Cf. A057732, A059242, A057195, A057196, A102633, A102634, A057197, A057200, A057221, A057201, A057203, A157006, A157007, A247952, A247953, A220077.
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KEYWORD
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nonn
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AUTHOR
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Edwin Dyke (ed.dyke(AT)btinternet.com), Feb 20 2009
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EXTENSIONS
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STATUS
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approved
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