Simplify

Author: fsimonis

growing-mesh/README.md

@@ -12,7 +12,7 @@ Get the [case files of this tutorial](https://github.com/precice/tutorials/tree/
 ## Setup
 
 The problem consists of a unit-square uniformly discretized by 768 x 768 nodes.
-Running in parallel is only allowed for $n^2, \exists n \in \mathbb{N}$.
+Running in parallel is only allowed for 1, 4, 9, or 16 ranks.
 The unit square is partitioned equally among the ranks of a solver.
 
 The mesh starts with 2 nodes in z direction and at a given frequency, 2 nodes are added to the mesh, changing only the load per rank, not the partitioning.