From 2 to 14: 12
From 14 to 98: 84
From 98 to 686: 588
There is no arithmetic sequence because the difference between each number is not the same each time.
Let's try dividing each number by the previous one:
14/2 = 7
98/14 = 7
686/98 = 7
Yes! It's a geometric sequence, multiplying by 7 with each step.