The number 7 is seen as lucky in slots and pop culture because it’s been tied...

https://wiki-velo.win/index.php/Why_Is_8_Lucky_in_Some_Cultures_but_7_Is_Lucky_in_Others%3F

The number 7 is seen as lucky in slots and pop culture because it’s been tied to good fortune for centuries. Classic reels often show triple 7s (777), signaling a big win