While looking for an answer to a different problem, I found the following example:

```
In[1]: = Array[Plus[##] &, {2,2}]Outside[1]= {{2,3}, {3,4}}
```

Having read the documentation of the `Space`

Y `SlotSequence`

, I understand the previous example. If we consider it as a matrix. $ M_ {ij} $, take the two indexes and add them, $ M_ {ij} = i + j $. I also understand that it is equivalent to `Training[Plus[#1,#2] &, {2, 2}]`

.

I tried to make the expression a bit more complicated:

```
In[2]: = Array[Plus[##,#] &, {2,2}]Outside[2]= {{3,4}, {5,6}}
```

that acts as $ M_ {ij} = (i + j) + i $, or if we replace the last `#`

with `# two`

, $ M_ {ij} = (i + j) + j $.

Now, I'm really stuck in the interpretation:

```
In[3]: = Array[Plus[## #] &, {2,2}]Outside[3]= {{1,2}, {4,8}}
```

What is the corresponding expression for $ M_ {ij} $?