[math-fun] Counting the letters of the line before

Hello MathFun, has someone computed this already? (same method as A005151) http://www.research.att.com/~njas/sequences/A005151 ZERO ONE E ONE O ONE R ONE Z FIVE E FOUR N FIVE O ONE R ONE Z FIVE E THREE F TWO I THREE N FOUR O TWO R ONE U TWO V ONE Z ... Any loop or fixed point? Best, É.