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A352162
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a(n) is the first start of a sequence of exactly n lower twin primes under the iteration p -> 3*p+2.
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0
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OFFSET
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1,1
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COMMENTS
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a(n), 3*a(n)+2, 9*(a(n)+1)-1, ..., 3^(n-1)*(a(n)+1)-1 are lower twin primes but 3^n*(a(n)+1)-1 is not.
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LINKS
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EXAMPLE
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a(3) = 32969 because 32969 and 32971 are primes, 3*32969+2 = 98909 and 98911 are primes, 3*98909+2 = 296729 and 296731 are primes, but 3*296729+2 = 890189 and 890191 are not both primes.
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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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STATUS
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approved
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