primes less than n and relatively prime to n--please folks!

Marc LeBrun mlb at well.com
Sat Jan 20 02:52:16 CET 2007


No, I don't think it's worth including.  (Which is not to say that 
there aren't many less interesting sequences in the OEIS.)

Note that you don't have to cut off the sum; you can take Sum_k 
floor(n/prime(k)) = floor(n/2) + floor(n/3) + floor(n/5) + ....

Of course that is in the OEIS: it's A013939.  You might find it 
worthwhile to take a look at it.

Franklin T. Adams-Watters


-----Original Message-----
From: jvospost3 at gmail.com

  I don't see in OEIS [n/2] + [n/3] + [n/5].
 which if I've done this right by hand begins for n = 1,2,3,...:
  0, 1, 2, 3, 4, 6, 6, 7, 7, 10, 10, 12, 12, 13, 15, 16, 16, 18, 18, 20, 
...

 ...

 I can't tell is this is artificial, or an interesting part of the
 supersequence which also includes, for instance:

 2 | [n/2] + [n/3]
 3 | [n/2] + [n/3] + [n/5]
 ...

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