This is an old unsolved problem. Erdos conjectured that for all $n\ge 9$ the ternary expansion of $2^n$ contains the ternary digit $2$ (this is equivalent to for every $n\ge 10$ the ternary expansion of $2^n$ contains a $1$). For recent work related to this (and references) see this paper of [Abram and Lagarias][1]. [1]: http://arxiv.org/pdf/1308.3133v1.pdf