Answer:
The pattern is adding by consecutive odds.
Step-by-step explanation:
The first odd you start with is 3:
1 + 3 = 4
4 + 5 = 9
9 + 7 = 16
16 + 9 = 25
25 + 11 = 36
...
Note that each time you add, it is by consecutive odds, meaning that after 36, you are adding 13, then 15, etc.
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