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A308050
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a(n) = n - prevprime(n - 1), where prevprime(n) is the largest prime < n.
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0
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2, 2, 3, 2, 3, 2, 3, 4, 5, 2, 3, 2, 3, 4, 5, 2, 3, 2, 3, 4, 5, 2, 3, 4, 5, 6, 7, 2, 3, 2, 3, 4, 5, 6, 7, 2, 3, 4, 5, 2, 3, 2, 3, 4, 5, 2, 3, 4, 5, 6, 7, 2, 3, 4, 5, 6, 7, 2, 3, 2, 3, 4, 5, 6, 7, 2, 3, 4, 5, 2, 3, 2, 3, 4, 5, 6, 7, 2, 3, 4, 5, 2, 3, 4, 5, 6
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OFFSET
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4,1
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COMMENTS
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a(n) is the smallest part appearing in the single partition of n into two parts whose largest prime part is < n - 1.
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LINKS
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FORMULA
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EXAMPLE
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a(11) = 4; 11 has 5 partitions into 2 parts: (10,1), (9,2), (8,3), (7,4) and (6,5). The single partition containing the largest prime part < 10 is (7,4) and 4 is the smallest part in this partition, so a(11) = 4.
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MATHEMATICA
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Table[n - NextPrime[n - 1, -1], {n, 4, 100}]
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CROSSREFS
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KEYWORD
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nonn,easy
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AUTHOR
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STATUS
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approved
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