From test case 2, it seems that you are asking for the closest prime number no less than n. Please clarify this ambiguity in the problem. Otherwise, the answer to test case 2 is 19 (not 23), which is the closest prime number to 20.
Final statement in problem statement disagrees with Case #1 of n=3.
I made a few quick edits.
I suggest to update this problem with big primes.
The Hitchhiker's Guide to MATLAB
Project Euler: Problem 7, Nth prime
Find the hypotenuse
multiple of nine?
Find the treasures in MATLAB Central and discover how the community can help you!
Choose a web site to get translated content where available and see local events and offers. Based on your location, we recommend that you select: .
You can also select a web site from the following list:
Select the China site (in Chinese or English) for best site performance. Other MathWorks country sites are not optimized for visits from your location.
Contact your local office