References:

  1. Inder J. Taneja, Single Digits Representations of Numbers from 1 to 20000,  https://inderjtaneja.com/2019/01/01/single-letter-representations-of-numbers-from-1-to-20000/
  2. Crazy Representations of Natural Numbers – The 10958 Problem
  3. Crazy Representations of Natural Numbers Using Factorial From 200001 to 300000
  4. Inder J. Taneja. (2020). Patterned Single Letter Representations of Natural NumbersZenodo, July 02, 2020, pp. 1-110, http://doi.org/10.5281/zenodo.3928507
  5. Inder J. Taneja, Factorial-Power Selfie Expressions, Zenodo, Feb 20, 2019, pp. 1-115,  https://doi.org/10.5281/zenodo.2573569