Hello Bruno,

It seems to me it's a bug in the documentation.
>
> Currently, column names are not allowed in the LHS (Left Hand Side) of
> the formula ('org-table-get-stored-formulas' assumes it).  Although I'm
> not sure why.
>

 However, the following, with the column name on the RHS, works

|---+----+----+----|
|   |  3 |  4 |    |
| ^ | c1 | c2 | c3 |
|---+----+----+----|
#+TBLFM: $c3 = $c1 + $c2

Could allowing column names on the LHS in my first example be put on a todo
list?

By the way, there is a small error in your example as your $3 should be $4.

Thanks,

Paul