In fan circles, the number 47 carries special significance for its frequent recurrence in dialog and on computer screens. Seemingly innocuous, the number has strangely achieved cult status among some fans.
The origin of the significance of 47 can be traced to The Next Generation and Voyager writer Joe Menosky, who attended Pomona College in California. There is a club at Pomona called The 47 Society, which claims that there exists a mathematical proof that all numbers are equal to 47, and that the number 47 occurs with greater frequency in nature than other numbers.
Joe Menosky first started including references to 47 in his scripts in the fourth season of TNG, and the in-joke quickly caught on among the rest of the staff. Since then, references to 47 have been included in virtually every episode of all the modern series.
When asked about the significance of the number, Rick Berman once joked, "47 is 42, corrected for inflation" referring to 42 being "the answer to the ultimate question of Life, the Universe, and Everything" according to The Hitchhiker's Guide to the Galaxy by Douglas Adams.
The number also seems to have some kind of significance to the writers and producers of the ABC series Alias, where it occurs almost as regularly as it does in Star Trek.