# [seqfan] Re: Contributing sequences with holes and infinities

Felix FrÃ¶hlich felix.froe at gmail.com
Fri Jun 17 15:49:34 CEST 2016

```Hi Christian,

regarding your first suggestion: isn't this A257479? Or am I
misunderstanding?

Regarding 2.: I think the usual way is to use a placeholder for terms that
have a value of infinity, like 0 or (if 0 can occur as a term in the
sequence, because number of groups for some n is 0, i.e., none exist) use a
value of -1. Thus, your sequence would become 1, 1, -1, 3, 5, 3, 4, 4, 4,
3, 3, 3, 3, .... I glanced at the OEIS Wiki but I am not sure if there is a
page where it is explicitly stated that 0 or -1 should be used for things
like inifinity or non-existing values. I think it might depend on the the
problem/sequence in question.

Maybe someone else will give a more authoritative answer.

Best regards
Felix

2016-06-17 15:13 GMT+02:00 Christian Stump <christian.stump at gmail.com>:

> Hi,
>
> I wonder whether it is okay to submit a sequence
>
> 1. with holes: an example would be a sequence related to the packing
> problem which is now solved in dimensions 0,1,2,3,8,24. So I wanted to
> add a sequence where only these entries are known.
>
> 2. with infinity entries: an example would be the number of
> irreducible reflection groups of a given rank. This sequence is
> 1,1,infinity,3,5,3,4,4,4,3,3,3,3,... .
>
> Please Ignore my ignorance, a link to the information would be
> appreciated, but i haven't found anything on the oeis website.
>
> Many thanks,
>
>     Christian
>
> --
> Seqfan Mailing list - http://list.seqfan.eu/
>
```