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Comment by cnvogel | Hacker News Reader

Quote from the Article: """The figure is calculated by multiplying 2 by itself 77,232,917 times and then subtracting 1."""

Would HN agree that multiplying 2 by itself once is 2⨯2 = pow(2,2), twice is 2⨯2⨯2 = pow(2,3) and N times yields pow(2,N+1)?

The Mersenne Prime found is pow(2,77232917) − 1, hence the article got the number wrong?

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If you're going that way, you can also interpret it - pardon my programming - as the following:

  int result; 
  for (int i = 0; i < 77232917; i++) { 
      result = 2 * 2; 
  } 
  return result - 1;

... which obviously results in 3. Also a (mersienne) prime, but not quite as big as you'd expect, and certainly not millions of digits long.

Yeah, I suppose if one wants to be pedantic. But we know what it means.

  int result; 
  for (int i = 0; i < 77232917; i++) { 
      result = 2 * 2; <----- you basically said result=4 77232917 times 
  } 
  return result - 1; <--- and then 4-1=3

so of course it will always be 3

That is the joke.

Dang ol' off-by-one errors.

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