4 ms·
Second attempt. 2^n has approximately n log 2 digits. Assuming that they are distributed randomly, the probability that none of these digits are 0 is (9/10)^(n
by qntm 15y ago
Second attempt.
2^n has approximately n log 2 digits. Assuming that they are distributed randomly, the probability that none of these digits are 0 is (9/10)^(n log 2).
For n = 50,000, this is already unbelievably tiny. For n = 50,001, it is even tinier. And so on.
In fact, summing all of these tiny probabilities from n = 50,000 to n = infinity is about the same as integrating (9/10)^(x log 2) from x = 50,000 to x = infinity, which is, again, only slightly above zero.
So, statistically at least, there is an excellent chance that every power of 2 above 50,000 has at least one zero.
- xyzzyz 15y agoAssuming that they are distributed randomly Well, this is what precisely needs to be proven. You cannot just assume that -- they're not distributed randomly in base 2, why they should be in base 10? They most likely are, but if you assume that, you are assuming the hypothesis.