# double factorial

> product of all the integers from 1 up to the integral input of the function that have the same parity as this input

**Wikidata**: [Q13520655](https://www.wikidata.org/wiki/Q13520655)  
**Wikipedia**: [English](https://en.wikipedia.org/wiki/Double_factorial)  
**Source**: https://4ort.xyz/entity/double-factorial


## References

1. Freebase Data Dumps. 2013