3x^2 + 6x -2

Lets do some spot-checks:

7,22,43,70,103,142,187,238

1,2 ,3 ,4 ,5 ,6 ,7 , 8

where x=1, y=3 * x^2 + 6 * x -2 = 3+6-2 = 7

where x=4, y=3 * x^2 + 6 * x -2 = 3*16 + 6*4 -2 = 48 + 14 -2 = 70

where x=8, y=3 * x^2 + 6 * x -2 = 3*64 + 6*8 -2 = 192 + 48 -2 = 238

Looks Good !