Number of words of length 2n-1 generated by the two letters s and t that reduce to the identity 1 by using the relations sssssss=1, tt=1 and stst=1. The generators s and t along with the three relations generate the 14-element dihedral group D7.
A072844
Number of words of length 2n-1 generated by the two letters s and t that reduce to the identity 1 by using the relations sssssss=1, tt=1 and stst=1. The generators s and t along with the three relations generate the 14-element dihedral group D7.
Terms
- a(0) =0a(1) =0a(2) =0a(3) =1a(4) =9a(5) =55a(6) =286a(7) =1365a(8) =6188a(9) =27132a(10) =116281a(11) =490337a(12) =2043275a(13) =8439210a(14) =34621041a(15) =141290436a(16) =574274008a(17) =2326683921a(18) =9402807817a(19) =37923176863a(20) =152705590518a(21) =614111175965
External references
- oeis: A072844