DLMF:

Figure 6.16.2 (See in context.)

Figure 6.16.2: The logarithmic integral $\mathop{\mathrm{li}\/}\nolimits\!\left(x\right)$ , together with vertical bars indicating the value of $\pi(x)$ for $x=10,20,\dots,1000$ .

Annotations:

Symbols:: $\mathop{\mathrm{li}\/}\nolimits\!\left(x\right)$ : logarithmic integral, $x$ : real variable and $\pi(x)$ : number of primes $\leq x$
Keywords:: logarithmic integral
Permalink:: http://dlmf.nist.gov/6.16.F2.mag
Encodings:: Magnified png, pdf