Year 31 (XXXI) was a common year starting on Monday (link will display the full calendar) of the Julian calendar. At the time, it was known as the Year of the Consulship of Augustus and Seianus (or, less frequently, year 784 Ab urbe condita). The denomination 31 for this year has been used since the early medieval period, when the Anno Domini calendar era became the prevalent method in Europe for naming years.

Telephone numbers in the Netherlands are administered by the Ministry of Economic Affairs, Agriculture and Innovation of the Netherlands and may be grouped into three general categories: geographical numbers, non-geographical numbers, and numbers for public services.

A vertical service code (VSC) is a special code dialed prior to (or instead of) a telephone number that engages some type of special telephone service or feature. Typically preceded with an asterisk, or * (star), key on the touch tone keypad and colloquially referred to as star codes, most are two digits in length; as more services are developed, those that use 2 or 3 as the first digit are sometimes three digits in length.