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What is the remainder when (3^18132 )is divided by 17?


The answer is 13.

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1 solution

Mateo Torres
Dec 19, 2013

Python code:

(3**18132)%17

cant it be done without coding????

Nurul Alam Pavel - 7 years, 5 months ago

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Yes, with Euler's Theorem. 3 and 17 are coprime so it can be applied.

ϕ ( 17 ) = 16 \phi(17) = 16 , because 17 is a prime number.

3 18132 = 3 16 1133 + 4 = ( 3 16 ) 1133 3 4 3 4 ( m o d 17 ) 3^{18132} = 3^{16 \cdot 1133 + 4} = (3^{16})^{1133}3^4 \equiv 3^4 \pmod{17}

And now 3 4 13 ( m o d 17 ) 3^4 \equiv \boxed{13} \pmod{17}

Ben Frankel - 7 years, 5 months ago

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