;Task:
Write a boolean function that tells whether a given integer is prime.


Remember that &nbsp; '''1''' &nbsp; and all non-positive numbers are not prime.

Use trial division.

Even numbers over two may be eliminated right away.

A loop from &nbsp; '''3''' &nbsp; to &nbsp; '''&radic;{{overline|&nbsp;n&nbsp;}} &nbsp;''' will suffice, &nbsp; but other loops are allowed.


;Related tasks:
* &nbsp; [[count in factors]]
* &nbsp; [[prime decomposition]]
* &nbsp; [[AKS test for primes]]
* &nbsp; [[factors of an integer]]
* &nbsp; [[Sieve of Eratosthenes]]
* &nbsp; [[factors of a Mersenne number]]
* &nbsp; [[trial factoring of a Mersenne number]]
* &nbsp; [[partition an integer X into N primes]]
* &nbsp; [[sequence of primes by Trial Division]]
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