Number 4 pinyin sì is considered an unlucky number in Chinese, Korean, Vietnamese and Japanese cultures because it is a homonym with the word "death" pinyin sǐ. Due to that, many numbered product lines skip the "4": e.g. Nokia cell phones (there is no series beginning with a 4), Palm PDAs, Canon PowerShot G's series (after G3 goes G5), etc. In East Asia, some buildings do not have a 4th floor. (Compare with the American practice of some buildings not having a 13th floor because 13 is considered unlucky.) In Hong Kong, some high-rise residential buildings miss ALL floor numbers with "4", e.g. 4, 14, 24, 34 and all 40-49 floors. As a result, a building whose highest floor is number 50 may actually have only 36 physical floors.
In Singapore during the early 2000s, Alfa Romeo introduced a new model, the 144. Nobody bought it, so they had to change the model number.
ALSO
Number 14 is considered to be one of the unluckiest numbers in Chinese culture. Although 14 is usually said as "shí sì," which sounds like "ten die", it can also be said as "yī sì" or "yāo sì", literally "one four". Thus, 14 can also be said as "yāo sì," literally "one four," but it also sounds like "want to die". In Cantonese, 14 sounds like "sap sei", which sounds like "sat sei" meaning "certainly die".
SO THATS WHY TQ SKIP D" NUMBER 4