

A063379


Number of orbits of the group of units of Z/(n) acting naturally on the 2subsets of Z/(n).


3



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, 45, 15, 71, 16, 49, 33, 37, 32, 86, 19, 41, 38, 81, 21, 91, 22, 65, 61, 49, 24, 123, 32, 73
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OFFSET

2,2


LINKS

Table of n, a(n) for n=2..50.


EXAMPLE

a(3) = 2 since when U(3) = {1,2} acts naturally on the three 2subsets {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}.


CROSSREFS

Cf. A065957, A063381, A000005, A056376 + 1, A056371  1
Sequence in context: A155749 A198931 A293779 * A000463 A137442 A111390
Adjacent sequences: A063376 A063377 A063378 * A063380 A063381 A063382


KEYWORD

nonn,more


AUTHOR

W. Edwin Clark, Jul 15 2001


STATUS

approved



