3 9 4 5 25 20 21 441
The pattern is, starting with 3
Square, subtract 5, add 1.
Repeat those three steps over and over:
Start with 3
Square, get 9
Subtract 5, get 4
Add 1, get 5
Square, get 25
Subtract 5, get 20
Add 1, get 21
Square, get 441
Subtract 5, get 436
Edwin