A Surprising Prime!

Number Theory Level 3

2 n + 17291729172917291729172917291729172917291729 2^n+17291729172917291729172917291729172917291729

Find the smallest value of n n such that the number above is a prime number .


The answer is 7.

Srinivasa Raghava by Srinivasa Raghava , 101, India

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1 solution

Fletcher Mattox
Aug 9, 2020 
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from sympy import isprime
for n in range(100):
    p = 2**n + 17291729172917291729172917291729172917291729
    if isprime(p):
        print(n)
        break

2 Helpful 0 Interesting 0 Brilliant 0 Confused

just amazing, thank you!

Alexander Shannon - 10 months ago

Interesting.

Srinivasa Raghava - 10 months ago

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Also, I owe you a "thank you" for this amazing question!

Alexander Shannon - 10 months ago

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Always welcome sir. I have a curious argument for this question. I will post.

Srinivasa Raghava - 10 months ago

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