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%I #7 Aug 13 2023 22:40:33
%S 1,4,16,62,48,109,84,2265,324,345,114,5359,217,636,2540,27908,218,
%T 2872,272,20933,4089,756,169,780487,892,1813,3015,30562,349,31419,510,
%U 191856,5096,1743,14139,115902,685,2156,13191,3764246,662,51063,600,38346,56222,1130,271
%N Number of conjugacy classes of subgroups of the group GL(2, Z_n) of invertible 2 X 2 matrices mod n.
%o (Magma) [#Subgroups(GL(2, ResidueClassRing(n))) : n in [2..50]];
%o (Sage) [len(GL(2, Zmod(n)).as_permutation_group().conjugacy_classes_subgroups()) for n in range(2, 50)]
%Y Cf. A000252, A066514.
%K nonn
%O 1,2
%A _Robin Visser_, Aug 12 2023