Conway's chained arrow notation

John H. Conway, Richard K. Guy "The Book of Numbers" 1996, pp.59-62

Pages on Conway's chained arrows from the Book of Numbers

Knuth's arrow functions

Donald Knuth "Mathematics and Computer Science: Coping with Finiteness" 1976
in: Campbell, Higgins "Mathematics people problems results, vol.2" 1984, p.210-211

Pages on arrow notation from an article by Donald Knuth