User blog comment:Swooped me in one hit/MCSICKLE/@comment-29310326-20170213182322/@comment-30754445-20170213232728

In BEAF it can be written exactly as {5,5,{5,5,2}}

In Chained Arrows it can be written exactly as 5→5→(5→5→2)

Niether notation has a simpler reasonable approximation, because it falls "between the cracks" as it were. In BEAF it falls between 3-arrays and 4-arrays. In Conway arrows it falls between the a→b→2→2 realm and the a→b→3→2 realm.

Note:

Using my own extension of BEAF linear arrays to nonintegers, we could write this number as {5,2+log 2/log 5,1,2} ~ {5,2.43,1,2}.