[seqfan] Re: Question regarding some sequences

Neil Sloane njasloane at gmail.com
Mon Dec 26 20:40:13 CET 2016


I am scanning the Read article and will add it to the couple of dozen
sequences that it mentions

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 Mon, Dec 26, 2016 at 1:57 PM, Sean A. Irvine <sairvin at gmail.com> wrote:

> I have a copy of the reference, but no way to scan.
>
> The definition of A036672 is the counting series for the stereo-isomers of
> all acyclic hydrocarbons. n is almost certainly the number of carbon atoms.
> The acyclic part should be added to the title. And A0036673 is the same
> thing, but with triple bonds excluded.  The reference gives a complicated
> looking three-variable generating function and cycle-index over A4 which
> can produce both these sequences.  There are dependencies on earlier
> generating functions as well (i.e. probably not a five minute job to extend
> these sequences via that formula or even to type the formula in). These
> sequences might be simple sums of some of the other counting series already
> present in the OEIS since the reference (as Neil mentions) contains a large
> number of sequences many of which are for counting various forms of
> alkanes, alkenes, etc.
>
> I will look into this further, but might be a few days.
>
>
> On 26 December 2016 at 16:25, Natan Consigli <origami.experience at gmail.com
> >
> wrote:
>
> > Dear Seqfans,
> >
> > I've come across A036672, A014236, I'm having a hard time
> > understanding which molecules are counted. Can someone explain me what
> > those sequences are exactly?
> >
> > I think I could better understand it if someone could show me which
> > ones are counted in the case of 4 carbon atoms.
> >
> > thanks in advance,
> >
> > Natan Consigli
> >
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> >
>
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>


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