Some people will think of the unlucky 13 in next years date, and to them it will not sound right.
2017 is still 4 years down the road, and sounds ok to me.
They sound fine to me.
Too many syllables..
Every year, near New Year's Eve, I practise saying the next year so I don't write the previous year on cheques, notes, etc.
2013 and 2017 don't sound right, does anyone else think that?