n1n2n1n22n1

n1n2n1n22n1 is a compact label used in discussions of symbolic sequences and string processing. As a string, it consists of five tokens written without separators: n1, n2, n1, n22, n1.

In formal language terms, it is a word over the alphabet {n1, n2, n22}. It serves as an example word to illustrate how concatenation operates in a token-based representation, and how different representations of the same underlying tokens can yield distinct character-length counts: the token sequence has length 5, while its character length is 11 if the tokens are written as their literal text (n1 has two characters, n2 has two, n22 has three).

The string can be generated or encountered in substitution systems and tokenization exercises. It is often used to illustrate the distinction between a sequence of tokens and its character-level representation, highlighting parsing decisions that depend on delimiter choices or token boundaries. As a run of five tokens, it also serves as a simple example in studies of prefix and suffix properties within word sequences.

Applications of this kind of label include teaching materials for formal languages, automata theory, and parsing algorithms. It provides a concrete case to discuss how token-based and character-based analyses can diverge, and how different tokenizations impact length, visibility of patterns, and parsing strategies.

See also: formal language theory, automata, string processing, morphisms, tokenization.