A229647 Cogrowth function of the group Baumslag-Solitar(5,5).

1, 4, 28, 232, 2092, 19864, 195376, 1971932, 20303084, 212400232, 2251379688, 24129199208, 261067326544, 2848016992032, 31295785633532, 346126420439512, 3850363854970476, 43057199315715676, 483795646775017312, 5459770924922887392

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(5,5)=<a,t | ta^5=a^5t>.

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: A229649 A359705 A229648 * A229646 A229645 A359798

Adjacent sequences: A229644 A229645 A229646 * A229648 A229649 A229650

Keyword

nonn,walk

Author

Murray Elder, Sep 27 2013

Status

approved