We learned how to find the Nth number in a term, and also how to check if it was really a geometric sequence or not. Geometric sequences use the formula An=A1+D to the exponent of (n-1). For example, if you had the sequence 2,8,14, 2 would be the first number in the sequence, or A1, d, or the common difference, is 6, while An is the term you're trying to find.