A364921 Number of conjugacy classes of subgroups of the group GL(2, Z_n) of invertible 2 X 2 matrices mod n.

1, 4, 16, 62, 48, 109, 84, 2265, 324, 345, 114, 5359, 217, 636, 2540, 27908, 218, 2872, 272, 20933, 4089, 756, 169, 780487, 892, 1813, 3015, 30562, 349, 31419, 510, 191856, 5096, 1743, 14139, 115902, 685, 2156, 13191, 3764246, 662, 51063, 600, 38346, 56222, 1130, 271

Offset: 1

Author

Robin Visser, Aug 12 2023

Keywords

• nonn

Crossrefs

Cf. A000252, A066514.

Programs

Magma

[#Subgroups(GL(2, ResidueClassRing(n))) : n in [2..50]];

Sage

[len(GL(2, Zmod(n)).as_permutation_group().conjugacy_classes_subgroups()) for n in range(2, 50)]