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A179684
The dimension of the space of invariant tensors in the n-th tensor power of the adjoint representation of the exceptional Lie algebra E6.
0
1, 0, 1, 1, 5, 17, 90, 542, 3962, 33554, 324489, 3520885, 42300709, 556530474, 7945317484, 122145525208, 2008827010000, 35143981009968
OFFSET
0,5
COMMENTS
This is known to satisfy a linear recurrence relation with polynomial coefficients. The limit of a(n+1)/a(n) is 78.
EXAMPLE
The n-th tensor power is the trivial representation for n=0 and is the adjoint representation for n=1. For n=2 every invariant tensor is a scalar multiple of a Killing form.
CROSSREFS
Sequence in context: A212291 A307176 A309175 * A250744 A197875 A203116
KEYWORD
nonn
AUTHOR
Bruce Westbury, Jul 24 2010
STATUS
approved