[seqfan] Re: Simple sequence not in the OEIS?

[brad klee]

> What puzzles me is that such a relatively simple sequence 
> is not present in OEIS even though there are a great many 
> sequences concerning paths on square lattices.

https://oeis.org/search?q=greek+key&go=Search

Did you see these? If I remember correctly, some of them 
came up as outputs from this graph transformer: 

https://resources.wolframcloud.com/FunctionRepository/resources/MultiwayDeletionsGraph/

MDG would probably also find solutions with neither start 
nor end point on the perimeter. It can accept any graph 
as a domain, and has an "edge-delete" method as well.   

Last summer a student from KU did some interesting work on 
mixed a mixed "edge-and-vertex-delete" method, but we didn't
have time to merge it into MDG: 

https://community.wolfram.com/groups/-/m/t/2575323

There are probably new sequences in there as well. 

--Brad