A229650 Cogrowth function of the group Baumslag-Solitar(8,8).

1, 4, 28, 232, 2092, 19864, 195352, 1970896, 20275660, 211823836, 2240798048, 23951367224, 258257552968, 2805581350056, 30676425237024, 337324008602512, 3727882769574860, 41381900166952348, 461201577710442388, 5158610797198820800

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(8,8)=<a,t | ta^8=a^8t>.

Links

Murray Elder, Table of n, a(n) for n = 0..50

M. Elder, A. Rechnitzer, E. J. Janse van Rensburg, T. Wong, The cogrowth series for BS(N,N) is D-finite

Index entries for sequences related to groups

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: A035610 A229652 A229651 * A229649 A359705 A229648

Adjacent sequences: A229647 A229648 A229649 * A229651 A229652 A229653

Keyword

nonn,walk

Author

Murray Elder, Sep 27 2013

Status

approved