Take any number (or anything that thinks it's a number) and multiply by thirteen.
From Wikipedia:
13 (thirteen /θɜrˈtiːn/) is the natural number following 12 and preceding 14.
In spoken English, the numbers 13 and 30 are often confused. When carefully enunciated, they differ in which syllable is stressed: 13 Listeni/θərˈtiːn/ vs. 30 /ˈθɜrti/. However, in dates such as 1300 ("thirteen hundred") or when contrasting numbers in the teens, such as 13, 14, 15, the stress shifts to the first syllable: 13 /ˈθɜrtiːn/.
This module is installed via npm:
$ npm install thirteenvar thirteen = require('thirteen');grunt