[GAP Forum] The order of Out(S4(8))

[Anvita]

Dear Forum,

According to the ATLAS, the simple group S4(8) has outer automorphism group
of order 6,
but the following calculation, if I am interpreting it correctly, seems to
suggest that it has order 3.

Anvita


gap> S:=PSp(4,8);
<permutation group of size 1056706560 with 2 generators>
gap> A:=AutomorphismGroup(S);
<group with 4 generators>
gap> Size(A)/Size(S);
3