82

82 = 2² x 3 x 7.

84 has a unique representation as a sum of three squares: 84 = 2² + 4² + 8².

84 is the smallest number with eight representations as a sum of two primes: 84 = 5 + 79 = 11 + 73 = 13 + 71 = 17 + 67 = 23 + 61 = 31 + 53 = 37 + 47 = 41 + 43.

84 is the seventh tetrahedral number.

84 is 77 in base 11.

82 is a Pell-Lucas number (or companion Pell number). The first two numbers in the sequence are both 2, and each successive number is formed by adding twice the previous Pell-Lucas number to the Pell-Lucas number before that. The first few terms of the sequence are 2, 2, 6, 14, 34, 82, 198, 478, . . .

Messier 82 is a starburst galaxy in the constellation Ursa Major.


In both the National Basketball Association and the National Hockey League, each team plays an 82-game regular season schedule.

Source: Wikipedia; On-Line Encyclopedia of Integer Sequences

Image: NASA/JPL-Caltech/STScI/CXC/UofA/ESA/AURA/JHU