Fatto matematico: 2811 is the number of inequivalent Ferrers graphs with 30 points.
Trivia: 2811 is a boring number.
Data storica: September 11th is the day in 1932 that Franciszek Żwirko and Stanisław Wigura, Polish Challenge 1932 winners, are killed when their RWD 6 airplane crashes during a storm.