The O'Nan group is a sporadic finite simple group of order 460815505920.  It is among the pariahs, not being a subquotient of the Monster.  It was discovered by Michael O'Nan in 1976.

The ONanGroup() command returns a permutation group isomorphic to the O'Nan group.

In the Standard Worksheet interface, you can insert this group into a document or worksheet by using the Group Constructors palette.

$\mathrm{with}\left(\mathrm{GroupTheory}\right)\:$

$G≔\mathrm{ONanGroup}\left(\right)$

$G≔O\text{'}Nan$

$\mathrm{Degree}\left(G\right)$

$122760$

$\mathrm{GroupOrder}\left(G\right)$

$460815505920$

$\mathrm{IsSimple}\left(G\right)$

$\mathrm{true}$

The GroupTheory[ONanGroup] command was introduced in Maple 17.

For more information on Maple 17 changes, see Updates in Maple 17.