Post date: Dec 4, 2019 8:09:10 PM
The fifth "lucky" number.
13 is the only integer that is, along with its fourth power, the sum of two consecutive squares:13 = 22 + 32 and 134 = 1192 + 1202
There are 13 Archimedian solids.
A scalene triangle having sides 13, 14 and 15 (consecutive integers) has an area that is also an integer (84 units2). Such triangles whose side lengths and area are all integers are called Heronian triangles.