x: basic frequency (Hz)    (number  > 0) 
    n: maximum harmonic factor (integer > 0)
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      ( x <= y          )
    &&(      y <= n * x )
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=for Example:
  sub Harmonics ($$) { ...add your code here... }
  print join( "\n", Harmonics( 100, 6 ) );
  # would print the following (without comments):
    100.000  # 100 * 1/1
    120.000  # 100 * 6/5
    125.000  # 100 * 5/4
    133.333  # 100 * 4/3
    150.000  # 100 * 3/2
    166.667  # 100 * 5/3
    200.000  # 100 * 2/1
    250.000  # 100 * 5/2
    300.000  # 100 * 3/1
    400.000  # 100 * 4/1
    500.000  # 100 * 5/1
    600.000  # 100 * 6/1
=cut
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Here's my little program, with a subroutine of 81 chars and warnings enabled:

#!usr/bin/perl -w
sub Harmonics ($$) {
for$i(1..$_[1]){for$j(1..$i){$y{sprintf"%.3f",$_[0]*$i/$j}=1}}sort{$a<
+=>$b}keys%y
}
print join( "\n", Harmonics( 100, 6 ) );
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update: no trailing zero supression was intended (fixed the example).
Thanx to BrowserUK for looking closely.

^~Django
"Why don't we ever challenge the spherical earth theory?"