Maximum error in the Prime Number Theorem
I'm finding 2 conflicting answers for maximum value that pi(n)/(n/ln(n)) can output, where pi(n) is the prime counting function and ln(n) is the natural log.
An inequality by Chebyshev says that the maximum is less than 9/8 (can be found at Prime Number Theorem -- from Wolfram MathWorld). However, setting n=13 we get pi(13)/(13/ln(13))≈1.255 (type it in to WolframAlpha to see for yourself) which is greater than 9/8.
So my question is, is something about Chebyshev's statement wrong (I doubt it), or am I misunderstanding something, and if so, what?