You've found the correct result; you just have to prove it. HINT: There's a bijection between the sets that contain $1$ and the sets that don't: if $1\in A$, pair $A$ with $A\setminus\{1\}$. Alternatively, each set that does not contain $1$ is a subset of the $(n-1)$-element set $\{2,\ldots,n\}$, and you know how many subsets that has.

Need help with a subsets problem
We currently use changesets to deploy to production for apex classes and configuration items. It is taking a long time for deployment because the validation on the production org takes a longer time to accomplish this. I know i can easily do a validation using ant to cut down the validation time but unfortunately the end user team does not allow this.Is there anything we can do to cut down the time taken to do the validate task for changesets in the production org?
Buyan
