What minimum exponent would give 100M digit prime?

[odin]

Hello All,

What minimum exponent value would give a 100M digit prime?

Also is there a calculator on the internet or that I could download that could give me the specific number that any exponent I use in the formula 2^P - 1?

Like to calculate the value of:

2^49254458 - 1?

Of course my computer's calculator gives infinity!!!!!

Thanks.

[CADavis]

http://mersenne-aries.sili.net/digits.php calculate number of digits from an exponent

i think it something above 332,000,000 for the exponent to give a 100M digit mersenne number.

[odin]

Originally Posted by CADavis

http://mersenne-aries.sili.net/digits.php calculate number of digits from an exponent

i think it something above 332,000,000 for the exponent to give a 100M digit mersenne number.

Thanks. You are right. I don't think I will be winning that prize. lol

[lfm]

Originally Posted by CADavis

http://mersenne-aries.sili.net/digits.php calculate number of digits from an exponent

i think it something above 332,000,000 for the exponent to give a 100M digit mersenne number.

Its pretty easy if you have a proper calculator. Just 1e6*ln(10)/ln(2)=3321928.09 or so.

[Uncwilly]

332192831 is the first prime that is 100 M digits.
There is a thread for those that TF'ing those in the range.

[10metreh]

Originally Posted by Uncwilly

332192831 is the first prime that is 100 M digits.

[pedant]No, it's the first prime p such that log₁₀(2^p-1) > 99,999,999.[/pedant]

[lfm]

Originally Posted by lfm

Its pretty easy if you have a proper calculator. Just 1e6*ln(10)/ln(2)=3321928.09 or so.

oops should be 1e8!

[Uncwilly]

Originally Posted by 10metreh

[pedant]No, it's the first prime p such that log₁₀(2^p-1) > 99,999,999.[/pedant]

You didn't see my [lazy shorthand][/lazy shorthand]?