%I A051881
%S A051881 1,1,1,2,1,2,1,2,1,2,1,3,1,2,1,2,1,2,1,2,1,2,1,3,1,2,1,2,1,2,1,2,1,2,1,
%T A051881 2,1,2,1,2,1,2,1,2,1,2,1,2,1,2,1,2,1,2,1,2,1,2,1,3,1,2,1,2,1,2,1,2,1,2,
%U A051881 1,2,1,2,1,2,1,2,1,2,1,2,1,2,1,2,1,2,1,2,1,2,1,2,1,2,1,2,1,2,1,2,1,2,1
%N A051881 Number of subgroups of order n in special orthogonal group SO(3).
%F A051881 Has period 1, 2 except for a(2) = 1, a(12) = a(24) = a(60) = 3.
%e A051881 The groups are "nn", of order n; "22n", of order 2n; "332", "432", "532" 
               of orders 12,24,60.
%Y A051881 The main sequences concerned with group theory are A000001, A000679, 
               A001034, A001051, A001228, A005180, A000019, A000637, A000638, A002106, 
               A005432, A051881.
%Y A051881 Sequence in context: A161275 A160979 A167679 this_sequence A081757 A033107 
               A083897
%Y A051881 Adjacent sequences: A051878 A051879 A051880 this_sequence A051882 A051883 
               A051884
%K A051881 nonn,easy,nice
%O A051881 1,4
%A A051881 J. H. Conway, conway(AT)math.princeton.edu
%E A051881 More terms from James A. Sellers (sellersj(AT)math.psu.edu) and David 
               W. Wilson (davidwwilson(AT)comcast.net) Dec 16 1999