Consider an=2an−1+1a_n = 2a_{n-1} + 1an=2an−1+1. Find the closed form given a0=0a_0 = 0a0=0.
2n−12^n - 12n−1
2n+12^n + 12n+1
2n+1−12^{n+1} - 12n+1−1
2n2n2n