Let be a nonnegative integer. The Landau's function of is defined in the following equivalent ways:
- The maximum possible value for the least common multiple of the parts in an unordered integer partition of .
- The maximum of the orders of all elements in the symmetric group of degree .
The value at is defined to be .
The ID of the sequence in the Online Encyclopedia of Integer Sequences is A000793
The values of Landau's function for is .