Quote:
Originally Posted by Dr Sardonicus
The number of decimal digits in 10*2^135091 would also be 2 + floor(13509*log(2)/log(10))...

I am going to spread this out a bit so I can read it better with my bad eyes. Sorry!
2 + floor(13509 * log(2) / log(10))
I carefully worked this through Windows Calculator and came up with 25,151. I am not sure about "floor" but it is familiar. So, I tried the same formula on this:
Code:
231*2^23352811 is prime! 702992 digits.
4,544,874. So I must not be doing something properly.