The Janko groups are the four sporadic groups ,
,
and
. The Janko group
is also known as the Hall-Janko group.
The Janko groups are implemented in the Wolfram Language as JankoGroupJ1[], JankoGroupJ2[], JankoGroupJ3[], and JankoGroupJ4[].
The following table summarized the group orders of the Janko groups.
| group | order | factorization |
| 175560 | ||
| 604800 | ||
| 50232960 | ||
| 86775571046077562880 |