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A229645 Cogrowth function of the group Baumslag-Solitar(3,3). 10
1, 4, 28, 232, 2108, 20364, 205696, 2149956, 23087260, 253400200, 2831688428, 32121034928, 368996930720, 4284878088040, 50221403053556, 593400572917032, 7061298334083484, 84555438345880932, 1018170456984477856, 12321676227943830972 (list; graph; refs; listen; history; text; internal format)
OFFSET
0,2
COMMENTS
a(n) is the number of words of length 2n in the letters a,a^{-1},t,t^{-1} that equal the identity of the group BS(3,3)=<a,t | ta^3=a^3t>.
LINKS
M. Elder, A. Rechnitzer, E. J. Janse van Rensburg, T. Wong, The cogrowth series for BS(N,N) is D-finite
EXAMPLE
For n=1 there are 4 words of length 2 equal to the identity: aa^{-1}, a^{-1}a, tt^{-1}, t^{-1}t.
CROSSREFS
The cogrowth sequences for BS(N,N) for N = 1..10 are A002894, A229644, A229645, A229646, A229647, A229648, A229649, A229650, A229651, A229652.
Sequence in context: A229648 A229647 A229646 * A359798 A307468 A202824
KEYWORD
nonn,walk
AUTHOR
Murray Elder, Sep 27 2013
STATUS
approved

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Last modified March 1 16:12 EST 2024. Contains 370442 sequences. (Running on oeis4.)