# harmonious chromatic number

> minimum number of colors needed for any harmonious coloring

**Wikidata**: [Q130418550](https://www.wikidata.org/wiki/Q130418550)  
**Wikipedia**: [English](https://en.wikipedia.org/wiki/Harmonius_chromatic_number)  
**Source**: https://4ort.xyz/entity/harmonious-chromatic-number


## References

1. On the harmonious chromatic number of a graph
2. The harmonious chromatic number and the achromatic number
3. Achromatic number versus pseudoachromatic number: a counterexample to a conjecture of Hedetniemi
4. Approximate and exact results for the harmonious chromatic number