A Notation for Large Numbers due to Steinhaus (1983) in which is defined in terms of Steinhaus-Moser Notation as in Squares. The particular number known as the Mega is then defined as follows.
See also Mega, Megistron, Steinhaus-Moser Notation
References
Steinhaus, H. Mathematical Snapshots, 3rd American ed. New York: Oxford University Press, pp. 28-29, 1983.