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A096366
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Known primitive friendly integers.
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2
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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
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,1
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COMMENTS
| 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.) [From Daniel Forgues (squid(AT)zensearch.com), Jun 24 2009]
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REFERENCES
| Anderson, Claude W. and Hickerson, Dean; Advanced Problem 6020, "Friendly Integers", Amer. Math. Monthly, 1977, V84#1p65-6.
Hickerson, Dean; "Re: Friendly number", post to sci.math newsgroup, 2000, available through groups.google.com.
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LINKS
| Walter Nissen, Home Page (listed in lieu of email address)
Walter Nissen, Primitive Friendly Integers and Exclusive Multiples, 2004 post to NMBRTHRY mailing list
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FORMULA
| Friends m and n are primitive friendly iff they have no common prime factor of the same multiplicity.
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EXAMPLE
| 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
| Cf. A014567, A074902, A095738, A095739.
Sequence in context: A096387 A094185 A074902 * A188158 A061822 A119840
Adjacent sequences: A096363 A096364 A096365 * A096367 A096368 A096369
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KEYWORD
| nonn
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AUTHOR
| Walter Nissen Jul 01 2004
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