Question

What is the next number of the following series: 8, 78, 318, 720, ?
Also tell the relation between 8,78

Answer 1

8, 78, 318, 720, 1276
70, 240,402, 556
170,162, 154
-8, -8

Or,

3^2 - 1 = 8
9^2 - 3 = 78
18^2 - 6 = 318
27^2 - 9 = 720
36^2 - 12 = 1284