Easy Sequences 7: Easy as Composite Pi - MATLAB Cody - MATLAB Central

Problem 52567. Easy Sequences 7: Easy as Composite Pi

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The prime Pi function is defined as the number of prime numbers from 1 to a certain given limit. In MATLAB, it is easy to create a prime Pi procedure, because there are built-in functions such as "primes" and "isprime". To calculate the prime Pi up to 100, we may just proceed as follows:
>> numel(primes(100))
>> ans =
25
>> nnz(isprime(1:100))
>> ans =
25
Can we make a function for "composite Pi", which is the number of composite numbers from 1 to a given limit, inclusive? Let's find out...
NOTE: The number '1' is considered as neither prime nor composite.
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Solution Stats

35.29% Correct | 64.71% Incorrect
Last Solution submitted on Sep 02, 2025

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