Triangles containing the origin II (noch nicht übersetzt)

Problem 456

Define:
x_n = (1248ⁿ mod 32323) - 16161
y_n = (8421ⁿ mod 30103) - 15051
P_n = {(x₁, y₁), (x₂, y₂), ..., (x_n, y_n)}

For example, P₈ = {(-14913, -6630), (-10161, 5625), (5226, 11896), (8340, -10778), (15852, -5203), (-15165, 11295), (-1427, -14495), (12407, 1060)}.

Let C(n) be the number of triangles whose vertices are in P_n which contain the origin in the interior.

Examples:
C(8) = 20
C(600) = 8950634
C(40 000) = 2666610948988

Find C(2 000 000).