On 2015 tax returns, the line # of the Health Care-Individual Responsibility penalty depends on which 1040 form you filed:
Form 1040 (long form)- line 61
Form 1040A - line 38
Form 1040EZ- line 11
This is where the penalty for not having health insurance for some or all of the year would have gone for 2015. Calculations flow from the Shared Responsibility Payment Worksheet.