The miscellaneous blog Futility Closet dug back into the archives of the New York Times to find this oddity: Between Feb. 7, 1898 and Jan. 1, 2000, the issue number of the front page of the paper was off by 500.
The Times issued a correction on that New Year’s Day:
On Feb. 6, 1898, it seems, someone preparing the next day’s front page tried to add 1 to the issue number in the upper left corner (14,499) and came up with 15,000. Apparently no one noticed, because the 500-issue error persisted until yesterday (No. 51,753). Today The Times turns back the clock to correct the sequence: this issue is No. 51,254.
Thus an article on March 14, 1995, celebrating the arrival of No. 50,000 was 500 days premature. It should have appeared on July 26, 1996.
The misnumbering was spotted by a diligent news assistant: “He wondered about the potential for self-perpetuating error. Using a spreadsheet program, he calculated the number of days since The Times’s founding, on Sept. 18, 1851. … Finally, by scanning books of historic front pages and reels of microfilm, Mr. Donovan zeroed in on the date of the 500-issue gap.”