Finding positive integer solutions to (2^n+1)/n²

[Davewilliams]

Find all positive integer answers for ((2^n)+1)/(n^2) where n is an integer greater then one.
The only answer i can find is three, i wrote a program to brute force it and have gotten up to n=32000 but as for going about solving it i have no clue.

 

[craigi]

Where did this question orginate?

 

[Davewilliams]

A friend from school broght it in... I have no clue where he got it from though.

 

[craigi]

A friend from school broght it in... I have no clue where he got it from though.

Is it homework?

 

[Davewilliams]

No, its just a problem we where trying to solve.