In following two works there are representations of natural numbers from 1 to 11111 in terms of single letter “a”.

- Inder J. Taneja, Fraction-Type Single Letter Representations of Natural Numbers From 1 to 11111,
**Zenodo**, February 4, 2019, pp. 1-203, http://doi.org/10.5281/zenodo.2556902. - Inder J. Taneja, Single Letter Representations of Natural Numbers from 1 to 11111,
**Zenodo**, February 5, 2019, pp. 1-133, http://doi.org/10.5281/zenodo.2557025.

These representations are two types. One as a natural way. The second one is of fraction-type. More details can be see at the following link:

This work brings patterns in single letter representations of natural numbers from 1 to 1000. Few examples of patterns are as follows:

More examples of similar kind can be seen at the following work:

- Inder J. Taneja, Patterned Single Letter Representations of Natural Numbers,
**Zenodo**, July 02, 2020, pp. 1-110, https://doi.org/10.5281/zenodo.3928507

For similar kind of pattern in terms of single digit see the link below:

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