Janko group

The term Janko group is used for one of the four sporadic simple groups whose existence was postulated by Zvonimir Janko. Of these, the first group $J_{1}$ was constructed by Janko and the remaining groups were constructed by others.

Group information	Symbol for group	Order	Prime factorization
Janko group:J1	$J_{1}$	175560	$2^{3}\cdot 3\cdot 5\cdot 7\cdot 11\cdot 19$
Janko group:J2, also called the Hall-Janko group	$J_{2}$ or $HJ$	604800	$2^{7}\cdot 3^{3}\cdot 5^{2}\cdot 7$
Janko group:J3	$J_{3}$	50232960	$2^{7}\cdot 3^{5}\cdot 5\cdot 17\cdot 19$
Janko group:J4	$J_{4}$	86775571046077562880	$2^{21}\cdot 3^{3}\cdot 5\cdot 7\cdot 11^{3}\cdot 23\cdot 29\cdot 31\cdot 37\cdot 43$