|
%I #6 Apr 23 2023 07:30:16
%S 1,2,4,3,9,4,11,8,13,6,25,7,17,18,24,9,33,10,35,23,25,12,59,18,29,26,
%T 45,15,71,16,49,33,37,32,86,19,41,38,81,21,91,22,65,61,49,24,123,32,
%U 73,48,75,27,105,46,103,53,61,30,181,31,65,78,98,53,131,34
%N Number of orbits of the group of units of Z/(n) acting naturally on the 2-subsets of Z/(n).
%e a(3) = 2 since when U(3) = {1,2} acts naturally on the three 2-subsets {0,1}, {0,2}, {1,2} of Z/(3) the orbits are {{0,1},{0,2}} and {{1,2}}. Note that 2{0,1} = {0,2} but there is no unit a in U(3) such that a{0,1} = {1,2}.
%Y Cf. A065957, A063381, A000005, A056376 + 1, A056371 - 1
%K nonn
%O 2,2
%A _W. Edwin Clark_, Jul 15 2001
%E More terms from _Sean A. Irvine_, Apr 22 2023
|
