Find the missing number in the sequence.
20, 19, 17, __ , 10, 5
12
13
14
16
Pattern is 20-1, 19-2, 17-3, 14-4, 10-5.
2, 8, 18, 32, 50, 72, (?)
56, 42, ?, 20, 12, 6, 2
996, 1000, 992, 1004, 988, ?, 984
4, 10, 40, 190, 940, ?, 23440