

A096366


Known primitive friendly integers.


6



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

0,1


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 2primitivefriendly (since they are all products of distinct powers of 2 and distinct Mersenne primes).  Daniel Forgues, Jun 24 2009


REFERENCES

Anderson, Claude W. and Hickerson, Dean; Advanced Problem 6020, "Friendly Integers", Amer. Math. Monthly, 1977, V84#1p656.
Hickerson, Dean; "Re: Friendly number", post to sci.math newsgroup, 2000, available through groups.google.com.


LINKS

Table of n, a(n) for n=0..25.
Walter Nissen, Primitive Friendly Integers and Exclusive Multiples, 2004 post to NMBRTHRY mailing list


FORMULA

Friends m and n are primitive friendly iff they have no common prime factor of the same multiplicity.


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.


CROSSREFS

Cf. A014567, A074902, A095738, A095739.
Sequence in context: A096387 A094185 A074902 * A247145 A188158 A061822
Adjacent sequences: A096363 A096364 A096365 * A096367 A096368 A096369


KEYWORD

nonn


AUTHOR

Walter Nissen, Jul 01 2004


STATUS

approved



