Black Friday Sale more than 50.000 users simultaneously accessed the site, temporarily causing delays and server overloads. The overwhelming numbers of visitors also caused the servers of several online shops, such as the electronics store Saturn, to suffer significant downtime. Despite the technical problems, the first Black Friday Sale generated a significant turnover and was considered a notable success by online retailers and organizers alike. After successfully launching in 2013, and having a successful 2014, 2015 and 2016, the Black Friday Sale is set to return on 24 November 2017. Online shoppers are expected to spend billions on this Black Friday sale. Once
Friday the 13th year being a common year starting on Tuesday (F) (e.g. 2001/02, 2012/13 and 2018/19), or from August to October the following year being a leap year starting on Saturday (BA) (e.g. 1999/2000 and 2027/28). The shortest period that occurs with a Friday the 13th is just one month, from February to March in a common year starting on Thursday (D) (e.g. 2009, 2015 and 2026). Each Gregorian 400-year cycle contains 146,097 days (with 97 leap days) or exactly 20,871 weeks. Therefore, each cycle contains the same pattern of days of the week and thus the same pattern of Fridays that