"math.integer" --- integer-specific mathematics functions
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在 3.15 版被加入.

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This module provides access to the mathematical functions defined for
integer arguments. These functions accept integers and objects that
implement the "__index__()" method which is used to convert the object
to an integer number.

The following functions are provided by this module.  All return
values are computed exactly and are integers.

math.integer.comb(n, k, /)

   Return the number of ways to choose *k* items from *n* items
   without repetition and without order.

   Evaluates to "n! / (k! * (n - k)!)" when "k <= n" and evaluates to
   zero when "k > n".

   Also called the binomial coefficient because it is equivalent to
   the coefficient of k-th term in polynomial expansion of "(1 + x)ⁿ".

   Raises "ValueError" if either of the arguments are negative.

math.integer.factorial(n, /)

   Return factorial of the nonnegative integer *n*.

math.integer.gcd(*integers)

   Return the greatest common divisor of the specified integer
   arguments. If any of the arguments is nonzero, then the returned
   value is the largest positive integer that is a divisor of all
   arguments.  If all arguments are zero, then the returned value is
   "0".  "gcd()" without arguments returns "0".

math.integer.isqrt(n, /)

   Return the integer square root of the nonnegative integer *n*. This
   is the floor of the exact square root of *n*, or equivalently the
   greatest integer *a* such that *a*² ≤ *n*.

   For some applications, it may be more convenient to have the least
   integer *a* such that *n* ≤ *a*², or in other words the ceiling of
   the exact square root of *n*. For positive *n*, this can be
   computed using "a = 1 + isqrt(n - 1)".

math.integer.lcm(*integers)

   Return the least common multiple of the specified integer
   arguments. If all arguments are nonzero, then the returned value is
   the smallest positive integer that is a multiple of all arguments.
   If any of the arguments is zero, then the returned value is "0".
   "lcm()" without arguments returns "1".

math.integer.perm(n, k=None, /)

   Return the number of ways to choose *k* items from *n* items
   without repetition and with order.

   Evaluates to "n! / (n - k)!" when "k <= n" and evaluates to zero
   when "k > n".

   If *k* is not specified or is "None", then *k* defaults to *n* and
   the function returns "n!".

   Raises "ValueError" if either of the arguments are negative.
