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%I #8 Mar 30 2012 18:37:41
%S 1,1,2,5,8,16,30,54,94,168,287,493,831,1391,2293,3769,6114,9867,15782,
%T 25098,39598,62165,96935,150398,232021,356261,544220,827758,1253222,
%U 1889655,2837455,4244505,6324993,9392009,13897056,20494991,30126628
%N Number of planar partitions of n, when partitions that are rotations of each other (when regarded as 3-D objects) are counted only once.
%C Plane partitions seen as 3-dimensional-objects can have a threefold symmetry axis.
%e n=3 gives 2 forms: {{3}}={{1,1,1}}={{1},{1},{1}} and {{2,1}}={{1,1},{1}}={{2},{1}}.
%Y Equals Cs + 2 C1 + 2 C3 + C3v, Cs=A000784, C1=A000785, C3=A048142, C3v=A048141. Cf. A000219, A005987.
%Y Or, equals (2*A048141+A000219+4*A048142)/3.
%K nonn
%O 1,3
%A _Wouter Meeussen_
%E Edited by _N. J. A. Sloane_, Oct 26 2008 at the suggestion of R. J. Mathar.
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