A number triangle of order n with entries 1 to n such that entries are nondecreasing across rows and down columns and all entries in column j are less than or equal to j. An example is 1 | | | | 1 | 1 | | | 1 | 1 | 1 | | 1 | 1 | 1 | 3 | 1 | 1 | 2 | 4 | 5. Magog triangles are in 1-to-1 correspondence with totally symmetric self-complementary plane partitions.

monotone triangle | plane partition