It is equal to one followed by an ecetonquadriplex zeroes. It is 1010101010303+1 digits long.
Writing down the full decimal expansion would take 1010101010303-6 books of 400 pages each, with 2,500 digits on each page (except for the first, which would have 2,501).
|Arrow notation||\(141\uparrow\uparrow 7\)|
|Chained arrow notation||\(141 \rightarrow 7 \rightarrow 2\)|
- Saibian, Sbiis. Hyper-E Numbers.