If an=2n⋅31−na_n = 2^n \cdot 3^{1-n}an=2n⋅31−n, which of the following is true?
Geometric, r=2/3r=2/3r=2/3
Geometric, r=3/2r=3/2r=3/2
Arithmetic, d=2d=2d=2
Neither