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A216519
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Prime numbers n such that 2^n-1 is a prime that cannot be written in the form a^2+7*b^2.
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1
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2, 5, 17, 89, 107, 521, 4253, 9689, 9941, 11213, 19937, 21701, 86243, 756839, 859433, 1398269, 2976221, 3021377, 6972593, 25964951, 32582657, 37156667, 43112609
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OFFSET
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1,1
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COMMENTS
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The terms are congruent to 2 (mod 3).
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LINKS
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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