[seqfan] Re: Just Qs not As!

[Zak Seidov]

 Correct/interesting or not,
a(n) = the smallest prime p such that p+2 is the product of exactly n primes (counting multiplicites).
Zak


>Среда,  3 февраля 2016, 13:14 -04:00 от "M. F. Hasler" <seqfan at hasler.fr>:
>
>On Wed, Feb 3, 2016 at 4:45 AM, Zak Seidov < zakseidov at mail.ru > wrote:
>
>> > Another my "sequence puzzle":
>> > 3, 2, 43, 79, 241, 727, 3643, 15307, 19681, 164023, 1673053, 885733,
>> > 2657203, 18600433, 23914843,100442347, 358722673, 645700813,?
>>
>> @ZakSeidov
>>
>
>Except for the 2 and 1673053 (which is strange anyway),
>seems to be a subsequence of
>oeis.org/A117679 = records in  A117677 = numdiv(n^2)-2, see below.
>
>In addition, these primes + 2 are of the form 3^k * (something very small)
>where "something" often is 1 or 5 or 7
>(again 1673053 +2 is the only one to have a  factor > 7).
>
>Maximilian
>
># b117679.txt - Table of n, a(n) for n=1..103 - Ray Chandler
>(rayjchandler(AT)sbcglobal.net), Dec 04 2008
>
>3 3
>
>8 43
>
>11 79
>
>16 241
>
>22 727
>
>31 3643
>
>45 15307
>
>49 19681
>
>70 164023
>
>89 885733
>
>103 2657203
>
>_______________________________________________
>
>Seqfan Mailing list -  http://list.seqfan.eu/