From the series, 2, 8, 18, 32, 50,...
By observation and by trial and error.
The first term, n = 1 = 211 = 2
Second term, n =2, = 222 = 8
Third, n =3, = 233 = 18
Third term, n = 4, = 244 = 32
Fourth term, n =5, 2 5 5 = 50
For nth term, 2 n n = 2n²
Therefore nth term = 2n²
I hope this helps.
