7
$\begingroup$

I understand all the other ones, but the $B'_L$ has me stumped. What does it mean and why is it equal to 1?

image

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    I have a watch with that symbol and, like the original poster, it was the only one I couldn't figure out. I agree that it appears to be Legendre's constant.2018-02-14

1 Answers 1

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It seems this is Legendre's constant

$ B^\prime_L = \lim_{n \to \infty}\left ( \log n - \frac{n}{\pi(n)} \right) $

where $\pi(n)$ stands the number of primes not exceeding $n$.

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    Álvaro Lozano-Robledo says in his MO answer that $B$ comes from Legendre, speculates that the subscript $L$ was added as a tribute to Legendre, and expresses puzzlement on the source of the apostrophe.2011-08-14