# [seqfan] Re: A123712 and A178212

Charles Greathouse charles.greathouse at case.edu
Thu Feb 9 16:30:57 CET 2012

```>> questions as it answers.  Why do we care about the number of nonzero
>> entries on a given row?  What is the significance of the constant 16?
>
> obviously the only motivation is the conincidence with A178212...

That was not the motivation for creating the sequence A123712, which
predates A178212 by four years.

Charles Greathouse
Analyst/Programmer
Case Western Reserve University

On Thu, Feb 9, 2012 at 9:57 AM, Maximilian Hasler
<maximilian.hasler at gmail.com> wrote:
>> questions as it answers.  Why do we care about the number of nonzero
>> entries on a given row?  What is the significance of the constant 16?
>
> obviously the only motivation is the conincidence with A178212...
>
> I computed the 2-analog :
>
> Numbers with bigomega > 2 but omega = 2 :
> 12,18,20,24,28,36,40,44,45,48,50,52,54,56,63,68,72,75,76,80,88,92,96,98,99,...
>
> which equals
>
> A123711                 Positions in A123709 equal to 8, so that row a(n) of
> triangle A123706 has exactly 8 nonzero terms.
>
> Feel free to conclude and write out the proof.
>
> Maximilian
>
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