IIT JEE Advanced 2009 Paper 1

The two possible cases are as follows:
Case 1: There are five 1’s; one 2; one 3. Therefore, the number of numbers is 7!/5! = 42.
Case 2: There are four 1’s; three 2’s. Therefore, the number of numbers is 7!/4! 3! = 35. Hence, the total number of numbers is 42 + 35 = 77