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A064812
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Smallest prime p such that the infinite sequence {p, p'=2p-1, p''=2p'-1, ...} begins with a string of exactly n primes.
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3
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5, 3, 2, 2131, 1531, 33301, 16651, 15514861, 857095381, 205528443121, 1389122693971, 216857744866621, 758083947856951, 107588900851484911, 69257563144280941
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OFFSET
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1,1
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COMMENTS
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Chains of length n of nearly doubled primes.
Smallest prime beginning a complete Cunningham chain of length n of the second kind. (For the first kind see A005602.) - Jonathan Sondow, Oct 30 2015
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LINKS
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EXAMPLE
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a(3) = 2 because 2 is the smallest prime such that the sequence {2, 3, 5, 9, ...} begins with exactly 3 primes, where each term in the sequence is twice the preceding term minus 1.
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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David Terr (dterr(AT)wolfram.com), Oct 21 2002
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STATUS
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approved
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