3= 1^2+2 2+ 1=3

7=3^2-2 1+3=4

18=4^2+2 2+4=7

47=7^2-2 4+7= 1 1

123= 1 1^2+2 7+ 1 1= 18

322= 18^2-2

That's it. One plus one MINUS one appears alternately, and the base of each is the sum of the first two.