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A136165
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a(n) = the number of divisors of n that are each not noncoprime to either the previous or the following divisor of n.
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6
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1, 2, 2, 1, 2, 2, 2, 1, 1, 2, 2, 3, 2, 2, 2, 1, 2, 2, 2, 1, 2, 2, 2, 3, 1, 2, 1, 1, 2, 4, 2, 1, 2, 2, 2, 3, 2, 2, 2, 2, 2, 2, 2, 1, 3, 2, 2, 3, 1, 2, 2, 1, 2, 2, 2, 2, 2, 2, 2, 5, 2, 2, 3, 1, 2, 2, 2, 1, 2, 4, 2, 3, 2, 2, 2, 1, 2, 2, 2, 2, 1, 2, 2, 4, 2, 2, 2, 1, 2, 4, 2, 1, 2, 2, 2, 3, 2, 2, 1, 1, 2, 2, 2, 1, 4
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OFFSET
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1,2
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LINKS
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EXAMPLE
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The divisors of 28 are 1,2,4,7,14,28. Among adjacent pairs of divisors, 1 and 2 are coprime and 4 and 7 are coprime. But 2 and 4 are adjacent divisors which are not coprime. And 7 is next to 14 among divisors of 28 and 7 and 14 are not coprime. Therefore there is a(28) = 1 divisor (1) that is not next to another divisor that it is not coprime to.
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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