[seqfan] Re: A099856 comes up

[Richard Guy]

This is a divisibility sequence and all my
earlier remarks apply.  Sorry that I don't
have the expertise to annotate the several
hundred sequences appropriately, nor to
add the several hundred missing sequences.
These are REAL sequences, which, as the
present example shows (no need for any
ongoing computation?) actually occur in
real life, often in more than one guise,
as opposed to the raft of artificial
sequences that seem to occupy most of us.

Best to all,    R.


On Thu, 26 Aug 2010, Ron Hardin wrote:

> http://www.research.att.com/~njas/sequences/A099856
> Expansion of (1+3x)/(1-3x).
>
> matches an ongoing computation of
> 1/20 the number of (n+1)X2 arrays of integers in 1..5 with no element or any of
> its neighbors having the same value
>
> which I guess shows the virtue of sometimes dividing by the first term.
>
>
> rhhardin at mindspring.com
> rhhardin at att.net (either)
>
>
>
>
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