Problem 369Published on Sunday, 29th January 2012, 04:00 am; Solved by 297; Difficulty rating: 60%
In a standard 52 card deck of playing cards, a set of 4 cards is a Badugi if it contains 4 cards with no pairs and no two cards of the same suit.
Let f(n) be the number of ways to choose n cards with a 4 card subset that is a Badugi. For example, there are 2598960 ways to choose five cards from a standard 52 card deck, of which 514800 contain a 4 card subset that is a Badugi, so f(5) = 514800.
Find ∑f(n) for 4 ≤ n ≤ 13.