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A128002
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Numbers k such that (31^k - 1)/30 is prime.
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9
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OFFSET
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1,1
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COMMENTS
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LINKS
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MATHEMATICA
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Select[Prime[Range[100]], PrimeQ[(31^#-1)/30]&]
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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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More terms from Herman Jamke (hermanjamke(AT)fastmail.fm), Jan 05 2008
a(8) = 535571 from Alexander Zhirkov, added by Paul Bourdelais, Jan 28 2021
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STATUS
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approved
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