[seqfan] Re: A076978

[Neil Sloane]

I have merged A076978 and A074168 (I declared the second one as dead, for
simplicity.  they were submitted by the same person at about the same time)

If someone would like to submit the sequence(s) that Don mentioned, go
ahead.  His b(n) - or perhaps B(n)? - seems to be A276378.



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.
Phone: 732 828 6098; home page: http://NeilSloane.com
Email: njasloane at gmail.com



On Wed, Dec 2, 2020 at 7:31 AM Neil Sloane <njasloane at gmail.com> wrote:

> No, let's not replace that old sequence. Leave it there (and edit it of
> course).  Make a new entry for the new sequence(s), please!
>
>
> 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.
> Phone: 732 828 6098; home page: http://NeilSloane.com
> Email: njasloane at gmail.com
>
>
>
> On Wed, Dec 2, 2020 at 3:42 AM Don Reble via SeqFan <seqfan at list.seqfan.eu>
> wrote:
>
>> Seqfans:
>>
>> > %S A076978
>> 1,2,6,30,6,210,6,2310,2730,30,39270,7410,42,7590,46410,1272810...
>> > %C A076978 Apparently a duplicate of A074168.
>> >            - _R. J. Mathar_, Sep 20 2008
>>
>>     Yeah, it's a duplicate. I propose a replacement.
>>
>>     A074168 has "1,2" and then squarefree multiples of 6.
>>     Which squarefree multiples are in the sequence? Perhaps all of
>>     them: but that would imply that the Twin Prime Conjecture is true.
>>
>>     The replacement: a(n) is the least positive integer x such that
>>     - the squarefree part of 6x is 6*b(n), and
>>     - 6x-1 and 6x+1 are prime.
>>     Or else "0" if there's no such x.
>>     B(n) is the n'th number that is both squarefree and coprime to 6.
>>
>>     (BTW, that b(n) isn't in the OEIS.)
>>
>> --
>> Don Reble  djr at nk.ca
>>
>>
>> --
>> Seqfan Mailing list - http://list.seqfan.eu/
>>
>