# [seqfan] Re: list of all non-prime coprimes of the full set of primorial numbers

Neil Sloane njasloane at gmail.com
Thu Apr 20 15:56:55 CEST 2017

```The definition is not clear.  Note that  gcd(121,2310)=11, so why is
121 on the list?
Or, if 121 is on the list, why not 49?

Also, what is Pn?  What is the difference between Pn(210) and 210 ?
Did you mean to say
Pn(4) = 210 rather than Pn(210)?
Best regards
Neil

Neil J. A. Sloane, President, OEIS Foundation.
11 South Adelaide Avenue, Highland Park, NJ 08904, USA.
Also Visiting Scientist, Math. Dept., Rutgers University, Piscataway, NJ.
Email: njasloane at gmail.com

On Thu, Apr 20, 2017 at 7:14 AM, Jamie Morken <jmorken at shaw.ca> wrote:
> Hi,
>
> Here is a sequence I added as a draft: https://oeis.org/draft/A285510
>
> It is a list of all non-prime coprimes of the full set of primorial numbers.
>
> b-file: https://oeis.org/draft/A285510/b285510.txt
>
> ie:
> Pn(2) has 1 coprime: 1
> Pn(6) has 2 coprimes: 1,5
> Pn(30) has 8 coprimes: 1,7,11,13,17,19,23,29
> Pn(210) has 48 coprimes: etc..
>
> The sequence is a complete list of all non-prime coprimes for all Pn.  The sequence starts:
>
> 1,121,143,169,187,209,221,247,289,299,323,361,377,391,403,437,481,493,527,529,533,551,559,589,611,629,
> 667,689,697,703,713,731,767,779,793,799,817,841,851,871,893,899,901,923,943,949,961,989,1003,1007,....
>
> Only large n values in the sequence will change when larger Pn are added to the set, values up to an increasingly
> large n will not change as larger Pn are added.
>
> cheers,
> Jamie
>
> --
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