Which sequence satisfies an=2an−1a_n = 2a_{n-1}an=2an−1 starting with a0=1a_0 = 1a0=1?
1,2,4,8,…1, 2, 4, 8, \dots1,2,4,8,…
1,3,5,7,…1, 3, 5, 7, \dots1,3,5,7,…
2,4,6,8,…2, 4, 6, 8, \dots2,4,6,8,…
1,1,2,4,…1, 1, 2, 4, \dots1,1,2,4,…