 The function li("x") has a single positive zero; it occurs at "x" ≈ 1.45136 92348 83381 05028 39684 85892 02744 94930... ; this number is known as the Ramanujan–Soldner constant.−Li(0) = li(2) ≈ 1.045163 780117 492784 844588 889194 613136 522615 578151...This is formula_6 where formula_7 is the incomplete gamma function.