>>530309537
you forgot about tails.
upon further calculations, it seems shitzzard is bending reality to make sure I never win
P(at least one run of HHHH or TTTT) ≈ 1 - exp(-((50 - 4 + 1) * 2) / (2^4)) = 1 - exp(-(47 * 2) / 16) = 1 - exp(-5.875) ≈ 0.997
