[seqfan] Re: Sequence contains only three elements 2, 4 and 6

[Charles Greathouse]

No such n exists, because it must be twice a prime and also a multiple of
3, and hence 6 is the only candidate.

At first I thought you meant sequences where all terms were 2, 4, or 6, in
which case I find 28 candidates
A007395 A010694 A010696 A010709 A010711 A010722 A019559 A040002 A040003
A046595 A061496 A067395 A071928 A074803 A092205 A105397 A125115 A130753
A138125 A145011 A156583 A164510 A165207 A194688 A226294 A236185 A236213
A239374
some of which can be removed fairly easily.

Charles Greathouse
Analyst/Programmer
Case Western Reserve University


On Sun, Mar 30, 2014 at 7:25 AM, Tw Mike <mt.kongtong at gmail.com> wrote:

> Dear Andrew,
>
> Thanks for your searching method,it's powerful.
> There's another seq [6]:
> numbers n that n/2 is prime, n and 2n between twin prime.
> a[0] is 6, a[1] maybe extreme large or doesnt exist.
> Supose OEIS has advanced web search such as a[0] == 6 and a[1] > 1e6.
>
> Yours mike,
>
>
> 2014-03-30 15:19 GMT+08:00 Andrew Weimholt <andrew.weimholt at gmail.com>:
>
> > Searching for "2,4,6 keyword:full" cuts the list to 39 sequences. Then
> > select the "short" format for easier viewing, and you can quickly examine
> > the results and see that there is currently no entry with 2,4,6 as its
> only
> > terms.
> >
> >
> >
> > On Sat, Mar 29, 2014 at 6:03 PM, Tw Mike <mt.kongtong at gmail.com> wrote:
> >
> > > Dear seqfans,
> > >
> > > There's a sequence contains only three elements 2, 4 and 6, search 2,
> 4,
> > 6
> > > on OEIS get more than three hundreds pages, how to know if this
> sequence
> > on
> > > OEIS?
> > >
> > > Yours mike,
> > >
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