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A048140 Number of planar partitions of n, but partitions that are mirror images of each other (when regarded as 3-D objects) are counted only once. 4
1, 2, 4, 8, 14, 27, 47, 86, 149, 261, 444, 760, 1269, 2119, 3486, 5711, 9247, 14906, 23800, 37816, 59622, 93528, 145759, 226071, 348612, 535131, 817280, 1242824, 1881310, 2836377, 4258509, 6369669, 9491142, 14092537, 20851146, 30749471 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Plane partitions seen as 3-dimensional-objects can have a mirror symmetry plane.

LINKS

Table of n, a(n) for n=1..36.

EXAMPLE

n=3 gives 4 forms: {{3}}; {{1,1,1}}={{1},{1},{1}}; {{2,1}}={{2},{1}}; {{1,1},{1}}.

CROSSREFS

Equals (A000219+A005987)/2.

Equals 2 Cs + 3 C1 + C3 + C3v, Cs=A000784, C1=A000785, C3=A048142, C3v=A048141. Cf. A000219, A005987.

Sequence in context: A164161 A068011 A048238 * A179817 A214255 A065616

Adjacent sequences:  A048137 A048138 A048139 * A048141 A048142 A048143

KEYWORD

nonn

AUTHOR

Wouter Meeussen

EXTENSIONS

Edited by N. J. A. Sloane at the suggestion of Andrew Plewe, Jun 08 2007

STATUS

approved

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Last modified June 23 15:27 EDT 2017. Contains 288666 sequences.