20132015
20132015 is a textual label formed by joining the numerals for the years 2013 and 2015. In practice it is used to denote the time period spanning 2013 through 2015, inclusive, especially in contexts where a compact or machine-readable representation is preferred over a written range such as 2013–2015 or 2013 to 2015.
Because the string lacks punctuation, its exact interpretation depends on context. It is most often read as
Typical uses include reporting on long-term projects, summarizing data over several consecutive years, or labeling files,
Formatting conventions favor the en dash form 2013–2015 in formal writing; the concatenated form is common
See also 2013, 2014, 2015, 2013–2015, time period, date range.