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xkcd #2897: Light Leap Years
(imgs.xkcd.com)
Alt text:
When Pope Gregory XIII briefly shortened the light-year in 1582, it led to navigational chaos and the loss of several Papal starships.
Okay, but now whenever you state one light year, it's just a normal year. When you state four, it is three normal ones and one leap year. So four times one light year would not equal four light years.
You asked for a lightyear adjusted based on leap years, I provided the number. It's a bit more than 365 light days and a bit less than 366 light days, it's closer to the real distance covered by light during the time the earth goes around the sun.
Edit: Don't know why anyone would downvote me for providing what OP asked for in the first place, especially when their reply didn't really make sense in the context...