triangular number: Media
mathematics
Images
Figure 2: Oblong numbers formed by doubling triangular numbers.
Encyclopædia Britannica, Inc.
The ancient Greeks generally thought of numbers in concrete terms, particularly as...
Encyclopædia Britannica, Inc.
Figure 1: Square numbers shown formed from consecutive triangular numbers.
Encyclopædia Britannica, Inc.
Figure 1: Polygonal arrays.
Encyclopædia Britannica, Inc.