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A096366
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Known primitive friendly integers.
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6
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6, 12, 24, 28, 30, 40, 42, 56, 60, 80, 84, 96, 108, 135, 140, 168, 200, 210, 224, 234, 240, 264, 270, 273, 480, 496
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OFFSET
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0,1
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COMMENTS
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There may be other primitive friendly integers within the range of those given, but they have yet to be calculated.
All perfect numbers are 2-primitive-friendly (since they are all products of distinct powers of 2 and distinct Mersenne primes). - Daniel Forgues, Jun 24 2009
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REFERENCES
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Hickerson, Dean; "Re: Friendly number", post to sci.math newsgroup, 2000, available through groups.google.com.
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LINKS
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Table of n, a(n) for n=0..25.
Claude W. Anderson and Dean Hickerson, Problem 6020: Friendly Integers, Amer. Math. Monthly 84 (1977) pp. 65-66.
Walter Nissen, Primitive Friendly Integers and Exclusive Multiples, 2004 post to NMBRTHRY mailing list
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FORMULA
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Friends m and n are primitive friendly iff they have no common prime factor of the same multiplicity.
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EXAMPLE
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While 6 and 28 are not coprime because they share the common factor 2, the factor 2 appears twice in 28 but only once in 6, so they are in the sequence.
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CROSSREFS
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Cf. A014567, A074902, A095738, A095739.
Sequence in context: A096387 A094185 A074902 * A247145 A188158 A061822
Adjacent sequences: A096363 A096364 A096365 * A096367 A096368 A096369
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KEYWORD
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nonn
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AUTHOR
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Walter Nissen, Jul 01 2004
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STATUS
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approved
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