Here's the instruction from IRS Form 8880 Credit for Qualified Retirement Savings Contributions:

Line 4.  Enter the total amount of distributions you, and your spouse if filing jointly, received after 2013 and before the due date of your 2016 return (including extensions) from any of the following types of plans.

So, to get a contribution credit, your 2016 contribution has to exceed the withdrawals taken in 2014, 2015, 2016 and up to October 15, 2017.  Next year that will all advance by one year.

The 2015 distribution will no longer be a factor for the 2018 tax year.