math_fact: 8320 is the number of subsets of {1, 1/2, 1/3, ... 1/42} that sum to an integer.
trivia: 8320 is an uninteresting number.
historical_date: October 11th is the day in 1982 that the Mary Rose, a Tudor carrack which sank on July 19, 1545, is salvaged from the sea bed of the Solent, off Portsmouth.