%I #12 Mar 12 2017 04:31:35
%S 1,1,4,13,57,252,1322,7361,45057,294392,2054394,15172872,118175823,
%T 966300054,8268640847,73825951226,686049132714,6620780612228,
%U 66224775509130,685372810735380,7327272883303533
%N Number of sets of sequences of total length n over an alphabet of n letters with the symmetric group acting on the letters.
%D E. Palmer and F. Harary, Graphical Enumeration, Academic Press, 1973.
%H Bob Lucassen, Marko Riedel, <a href="http://math.stackexchange.com/questions/2180525">Counting sets of unlabeled sequences of total cardinality n</a>
%H Marko Riedel, <a href="/A283612/a283612_1.maple.txt">Maple code for A283612 by total enumeration and by Power Group Enumeration.</a>
%K nonn,more
%O 0,3
%A _Marko Riedel_, Mar 11 2017