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A195732
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Numbers k such that 2*(3^k-k)-1 is prime.
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1
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1, 2, 3, 11, 30, 62, 534, 620, 803, 2436, 2669, 3975, 4530, 4827, 5294, 15987, 17589, 51960
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OFFSET
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1,2
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COMMENTS
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According to Maple version 14, the next entries are 534, 620 and 803, but these involve primes of 256 and more digits and may not be certified primes. - R. J. Mathar, Sep 23 2011
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LINKS
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EXAMPLE
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1 is in the sequence because 2*3^1-2*1-1 = 3 is a prime, 2 is in the sequence because 2*3^2-2*2-1 = 13 is a prime, 3 is in the sequence because 2*3^3-2*3-1=47 ts a prime, 4 is not in the sequence because 2*3^4-2*4-1 = 153 = 3^2*17 is not prime.
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PROG
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CROSSREFS
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KEYWORD
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nonn,more
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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