yaworsw/euler-manager

---
:id: 383
:name: Divisibility comparison between factorials
:url: https://projecteuler.net/problem=383
:content: "Let f<sub>5</sub>(<var>n</var>) be the largest integer <var>x</var> for
  which 5<sup><var>x</var></sup> divides <var>n</var>.  \nFor example, f<sub>5</sub>(625000)
  = 7.\n\nLet T<sub>5</sub>(<var>n</var>) be the number of integers <var>i</var> which
  satisfy f<sub>5</sub>((2·<var>i</var>-1)!) \\< 2·f<sub>5</sub>(<var>i</var>!) and
  1 ≤ <var>i</var> ≤ <var>n</var>.  \nIt can be verified that T<sub>5</sub>(10<sup>3</sup>)
  = 68 and T<sub>5</sub>(10<sup>9</sup>) = 2408210.\n\nFind T<sub>5</sub>(10<sup>18</sup>).\n\n"