Cube division by planes is the problem of determining the regions into which planes divide a cube. The average number of regions produced by randomly chosen planes is
(Yaglom and Yaglom 1987, pp. 102-106). For , 2, ... planes, this gives the values 2, 4, 8, 15, 26, 42,
... (OEIS A000125), a sequence whose values
are sometimes called the "cake numbers"
due to their relation to the cake cutting problem.