

A181119


Transposecomplementary plane partitions


1



1, 2, 84, 81796, 1844536720, 962310111888300, 11608208114358751650000, 3236574482779383546336417240000, 20853456581643133066208521560263633137920, 3104385823530881109001458753652585998600603921849920, 10676554307318599842868990948461304923921623250562199975300214736
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OFFSET

0,2


COMMENTS

The complement of a plane partition inside an m*m*m cube consists of the boxes which are within the cube, but not in the plane partition, rotated in an appropriate way.
a(n) is the number of plane partitions inside an 2n*2n*2n cube whose (matrix) transpose when written as an 2n*2n array is the same as its complement.


REFERENCES

Richard Stanley, Symmetries of plane partitions, J. Combin. Theory Ser. A 43 (1986), no. 1, 103113.


LINKS

Table of n, a(n) for n=0..10.
Wikipedia, Plane partition


FORMULA

a(n) = binomial(3n1,n)*Product(i=1..2n2,Product(j=i..2n2,(2n+i+j+1)/(i+j+1)))


EXAMPLE

When n=2, there are two transposecomplementary plane partitions,
[1 1] and [2 1], both of whose transpose and complement is equal to themselves.
[1 1] [1 0]


MATHEMATICA

Table[Binomial[3n1, n]Product[(2n+i+j+1)/(i+j+1), {i, 1, 2n2}, {j, i, 2n2}], {n, 0, 10}] (* Harvey P. Dale, Jan 27 2012 *)


CROSSREFS

Cf. A008793, A051255, A078920, A123352
Sequence in context: A205643 A215263 A157063 * A157315 A078166 A101578
Adjacent sequences: A181116 A181117 A181118 * A181120 A181121 A181122


KEYWORD

nonn,nice


AUTHOR

Arvind Ayyer, Jan 21 2011


STATUS

approved



