the next number would be 50. if you find the difference between each set of numbers (i.e. 145-122), you'll notice that as you subtract, every number goes down by 2. so, I'll write it out for you:
145-122=23
122-101=21
101-82=19
82-65=17
and finally, you would see, that through the pattern, the next number should be 15. so, 65-15=50.
