Which of these is the recursive formula for the sequence 3,6,12,24,…3, 6, 12, 24, \dots3,6,12,24,…?
an=2an−1a_n = 2a_{n-1}an=2an−1
an=an−1+6a_n = a_{n-1} + 6an=an−1+6
an=3an−1a_n = 3a_{n-1}an=3an−1
an=an−1+3a_n = a_{n-1} + 3an=an−1+3