What is the complexity of this nested triple for loop?

Question

I have searched a bit on StackOverflow and have understood the complexity up to the point of the j-loop, which is O(n2). However with the nested addi

Answer 1

If you're accustomed to Sigma Notation, here is a formal way to deduce the time complexity of your algorithm (the plain nested loops, precisely):

NB: the formula simplifications might contain errors. If you detect anything, please let me know.