Gambling and luck\n\n 777 is used on most slot machines in the United States to identify a jackpot. As it is considered a lucky number, banknotes with a serial number containing 777 tend to be valued by collectors and numismatists.
There are very popular slot machines that have been around for many years called the red, white and blue triple 7 three reel slots. They feature tri- colored 7 symbols where you win varying amounts if you can line up three 7 2s in a row on the center line.