# Find 25-vertex 4-regular planar graphs using plantri

I am using SageMath 9.2 and I have recently wanted to add the optional package **plantri**.
I found a link to a similar question before:
Ask Sage question 52358
where a comment suggests this command:

```
sage: !sage -i plantri
```

An error occurred during the installation process that prevented it from proceeding.

```
make[3345]: Entering directory '/opt/sagemath-9.2'
0 [main] make (45584) C:\Users\asus\AppData\Local\SageMath 9.2\runtime\bin
\make.exe: *** fatal error in forked process - ccalloc would have returned NULL
0 [main] make 15063 dofork: child -1 - forked process 45584 died unexpect
dly, retry 0, exit code 0xC0000142, errno 11
make[3345]: *** [Makefile:31: bootstrap] Error 127
```

My computer runs the Windows10 64-bit operating system. I don't know how to solve this installation problem.

In fact, the graph theory problem I encountered is as follows.

I 'd like to generate all **25-vertex 4 regular planar graphs that size of maximum face is 4**.
Of course it may not exist.

With the help of plantri, I think there should be no problem, because I saw James Preen's page on the degree-diameter problem, which contains the following paragraph.

Additionally, using plantri it has been established that there exist

no 4-regular planar graphs with 28vertices and similarly there are no 3-regular planar graphs with diameter 4 with between 20 and 30 vertices.

If someone has successfully installed it, can you help me see if there is such a graph?

Thanks in advance！

```
sage: for G in graphs.planar_graphs(25, minimum_degree=4):
....: if G.num_edges==50:
sage: show(G)
sage: print("nofind")
```

The above codes may need improvement.

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