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Computer Science Level 5

Find the smallest prime factor p > 3 p> 3 of 200 ! + 200 ! ! + 2 ! ! ! + 1 200!+200!!+2!!!+1 .

Review double factorials and multifactorials to understand what 200 ! ! 200!! and 2 ! ! ! 2!!! refers to.


The answer is 227.

Sal Gard by Sal Gard , 19, USA

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1 solution

Mehdi K.
Jun 8, 2016 
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>>> def mf(n, k):     #multi-factorial
...     if n <= k: return n
...     return n * mf(n - k, k)
... 
>>> a = mf(200, 1) + mf(200, 2) + 3      #2!!! = 2
>>> p = 5
>>> while True:
...     if a % p == 0:
...         print(10001 * p)
...         break
...     p += 2
... 
2270227

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