Your statement is just as senseless as your exercise, which is unsurprising. Where are the arguments? Here are mine: you found the formula, you rewrote the formula, done. You don't even need to know syntax for this; for the sake of experiment, I solved this kata in C++ and C# (had issues with C for understandable reasons) despite knowing next to nothing about these languages. Why? Because all that's needed for this kata is the mathematical formula and the syntax of the ternary operator.

1. Read about arithmetic series formula
2. Use floor division in this formula

Just another pointless math kata, has nothing to do with programming