[quote=Sketcher]
No... in the last chapter, after Light's death, he's known as L.And we know N isn't dead because he did a trick where he set a certain date of death for himself so Kira couldn't kill him with the notebook.
[/quote]

The rules seem to be that the maximum length of time you could have as a result of writing your name in the death note is 23 days. If the death would take 24 days or longer they just die in the normal heart attack in 6 minutes 40 seconds instead. Therefore, all you're doing with that plan is buying yourself time to not get killed by the death note immediately. If the death note worked forever you could become practically immortal by saying you die at whatever age you prefer.