Which number should come next? 145,122,101,82,65

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.

The pattern seems to be decreasing by a number that is also decreasing by 2 each time, so after 65 comes 50.