OFFSET
1,2
COMMENTS
Friends x and y are primitive friendly if and only if they have no common prime factor with the same multiplicity, that is, if A165430(x, y) = 1.
LINKS
Walter Nissen, Primitive Friendly Integers and Exclusive Multiples, Up for the Count!
Eric Weisstein's World of Mathematics, Friendly Pair.
EXAMPLE
The first pair (6, 28) is primitive since 6=2*3 and 28=2^2*7; their only common prime factor, 2, appears with different exponents, so 1 is a term.
The second pair (30, 140) is not primitive since 30=5*6 and 140=5*28; the prime factor 5 appears in each with the same exponent, so 2 is not a term.
PROG
CROSSREFS
KEYWORD
nonn
AUTHOR
Michel Marcus, Oct 10 2015
STATUS
approved