A060817 Size of the automorphism group of the alternating group A_n.

1, 1, 2, 24, 120, 1440, 5040, 40320, 362880, 3628800, 39916800, 479001600, 6227020800, 87178291200, 1307674368000, 20922789888000, 355687428096000, 6402373705728000, 121645100408832000, 2432902008176640000

Offset: 1

Author

Ola Veshta (olaveshta(AT)my-deja.com), Apr 29 2001

Keywords

• nonn

Comments

For all n except n=2, n=3 and n=6, Aut(A_n) is S_n, i.e., a(n) = n!, while Aut(A_2) = S_1, Aut(A_3) = Aut(C_3) = C_2 = S_2 and Aut(A_6) contains S_6 as a subgroup of index 2.

Crossrefs

Cf. A001710, A060249.