L_i

\pi

Note : 
Séquence((n, NbSi(EstPremier(a), a, Séquence(n))), n, 1, 16000)

c_2 = 0
f = Integral(1 / log(x), x)
c_1 = 0
c_3 = 0
n = 8880 (slider from 0 to 16000, step 1)
c = CountIf(IsPrime[a], a, Sequence[n])
A: (n, c)
Li(x) = If[2 ≤ x ≤ 16000, f(x) - f(2)]