Number of words of length 2n generated by the two letters s and t that reduce to the identity 1 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.
A072266
Number of words of length 2n generated by the two letters s and t that reduce to the identity 1 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) =1a(1) =1a(2) =3a(3) =10a(4) =35a(5) =126a(6) =462a(7) =1717a(8) =6451a(9) =24463a(10) =93518a(11) =360031a(12) =1394582a(13) =5430530a(14) =21242341a(15) =83411715a(16) =328589491a(17) =1297937234a(18) =5138431851a(19) =20380608990a(20) =80960325670a(21) =322016144629
External references
- oeis: A072266