The irregularity of distributions problem, stated first by Hugo Steinhaus, is a numerical problem with a surprising result. The problem is to find N numbers,                               x                      1                          ,        …        ,                  x                      N                                  , all between 0 and 1, for which the following conditions hold:
The first two numbers must be in different halves (one less than 1/2, one greater than 1/2).The first 3 numbers must be in different thirds (one less than 1/3, one between 1/3 and 2/3, one greater than 2/3).The first 4 numbers must be in different fourths.The first 5 numbers must be in different fifths.etc.Mathematically, we are looking for a sequence of real numbers
                              x                      1                          ,        …        ,                  x                      N                                  such that for every n ∈ {1, ..., N} and every k ∈ {1, ..., n} there is some i ∈ {1, ..., n} such that
                                                        k              −              1                        n                          ≤                  x                      i                          <                              k            n                          .                The surprising result is that there is a solution up to N = 17, but starting at N = 18 and above it is impossible. A possible solution for N ≤ 17 is shown diagrammatically on the right; numerically it is as follows:
                                                                                          x                                      1                                                                                              =                0.029                                                                                      x                                      2                                                                                              =                0.971                                                                                      x                                      3                                                                                              =                0.423                                                                                      x                                      4                                                                                              =                0.71                                                                                      x                                      5                                                                                              =                0.27                                                                                      x                                      6                                                                                              =                0.542                                                                                      x                                      7                                                                                              =                0.852                                                                                      x                                      8                                                                                              =                0.172                                                                                      x                                      9                                                                                              =                0.62                                                                                      x                                      10                                                                                              =                0.355                                                                                      x                                      11                                                                                              =                0.774                                                                                      x                                      12                                                                                              =                0.114                                                                                      x                                      13                                                                                              =                0.485                                                                                      x                                      14                                                                                              =                0.926                                                                                      x                                      15                                                                                              =                0.207                                                                                      x                                      16                                                                                              =                0.677                                                                                      x                                      17                                                                                              =                0.297                                                            In this example, considering for instance the first 5 numbers, we have
                    0        <                  x                      1                          <                              1            5                          <                  x                      5                          <                              2            5                          <                  x                      3                          <                              3            5                          <                  x                      4                          <                              4            5                          <                  x                      2                          <        1.