Expression Nodes is a Blender add-on from Hamed Zaghaghi that generates math nodes directly from a formula. Instead of adding many math nodes and connecting them together to implement a simple formula, you write the expression and let the add-on build the node setup.
The workflow is direct: type the formula, press the Create Nodes button, and the nodes appear. It runs in any Blender node editor that includes a math node, so the same approach applies wherever those nodes are used.
Expression Nodes lists compatibility with Blender 3.0 and 3.1 and ships with documentation. A demo video is also available. It's listed as free here, under a royalty-free license, and has recorded more than forty sales since it was published about four years ago.