Английская Википедия:222 (number)

Материал из Онлайн справочника
Перейти к навигацииПерейти к поиску

Шаблон:Other uses Шаблон:Infobox number 222 (two hundred [and] twenty-two) is the natural number following 221 and preceding 223.

In mathematics

It is a decimal repdigit[1] and a strobogrammatic number (meaning that it looks the same turned upside down on a calculator display).[2] It is one of the numbers whose digit sum in decimal is the same as it is in binary.[3]

222 is a noncototient, meaning that it cannot be written in the form n − φ(n) where φ is Euler's totient function counting the number of values that are smaller than n and relatively prime to it.[4]

There are exactly 222 distinct ways of assigning a meet and join operation to a set of ten unlabelled elements in order to give them the structure of a lattice,[5] and exactly 222 different six-edge polysticks.[6]

References

Шаблон:Reflist

Шаблон:Integers