[seqfan] Re: Kaku-Stroke-Bus route
Giovanni Resta
g.resta at iit.cnr.it
Tue Jun 14 10:35:43 CEST 2016
On 06/14/2016 05:20 AM, zbi74583.boat at orange.zero.jp wrote:
> Hi,Seqfans
>
> "Bus route" is the same thing as "Stroke" on non directed graph.
> See the definition on A131709
>
> To compute number of partition of graph into "Bus route" is rather difficult
> even if graph is easy as follows.
>
> nxn grid See A135442
> K_n See A135444
> Could anyone confirm them and compute more term?
I think I have some difficulties understanding the
definition and/or reconcile A131709 and A135442.
A131709 is Number of partitions into "bus routes" of an n X 1 grid.
while
A135442 Number of partitions into "bus routes" of n X n grid.
but why A131709(1) = 14 and A135442(1) = 4 ?
They should be equal unless the two sequences uses a different
definition of "partitions into bus routes".
I have also some difficulties understanding the nature
of bus routes. It seems they are directed paths.
However, in A135444 (Number of partitions into "bus routes" of K_n.)
we have a(2)=1.
If the routes are directed, I would have expected a(2)=2, because there
are two routes: 1 => 2 and 2 => 1.
Probably there is something that I do not grasp. Is it possible to have
a list of the 14 (or 4 ??) partitions of the grid 1 X 1 and/or the 3
partitions of K_3, to better understand ?
Giovanni
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