| 1 | a | b | a2 | ba | b2 | ba2 | b2a | b3 | b2a2 | b3a | b4 | b3a2 | b4a | b5 | b4a2 | b5a | b6 | b5a2 | b6a | b6a2 | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1 | 1 | a | b | a2 | ba | b2 | ba2 | b2a | b3 | b2a2 | b3a | b4 | b3a2 | b4a | b5 | b4a2 | b5a | b6 | b5a2 | b6a | b6a2 |
| a | a | a2 | b4 | a | b4a | b5 | b4a2 | b5a | b6 | b5a2 | b6a | b | b6a2 | ba | b2 | ba2 | b2a | b3 | b2a2 | b3a | b3a2 |
| b | b | ba | b2 | ba2 | b2a | b3 | b2a2 | b3a | b4 | b3a2 | b4a | b5 | b4a2 | b5a | b6 | b5a2 | b6a | b | b6a2 | ba | ba2 |
| a2 | a2 | a | b | a2 | ba | b2 | ba2 | b2a | b3 | b2a2 | b3a | b4 | b3a2 | b4a | b5 | b4a2 | b5a | b6 | b5a2 | b6a | b6a2 |
| ba | ba | ba2 | b5 | ba | b5a | b6 | b5a2 | b6a | b | b6a2 | ba | b2 | ba2 | b2a | b3 | b2a2 | b3a | b4 | b3a2 | b4a | b4a2 |
| b2 | b2 | b2a | b3 | b2a2 | b3a | b4 | b3a2 | b4a | b5 | b4a2 | b5a | b6 | b5a2 | b6a | b | b6a2 | ba | b2 | ba2 | b2a | b2a2 |
| ba2 | ba2 | ba | b2 | ba2 | b2a | b3 | b2a2 | b3a | b4 | b3a2 | b4a | b5 | b4a2 | b5a | b6 | b5a2 | b6a | b | b6a2 | ba | ba2 |
| b2a | b2a | b2a2 | b6 | b2a | b6a | b | b6a2 | ba | b2 | ba2 | b2a | b3 | b2a2 | b3a | b4 | b3a2 | b4a | b5 | b4a2 | b5a | b5a2 |
| b3 | b3 | b3a | b4 | b3a2 | b4a | b5 | b4a2 | b5a | b6 | b5a2 | b6a | b | b6a2 | ba | b2 | ba2 | b2a | b3 | b2a2 | b3a | b3a2 |
| b2a2 | b2a2 | b2a | b3 | b2a2 | b3a | b4 | b3a2 | b4a | b5 | b4a2 | b5a | b6 | b5a2 | b6a | b | b6a2 | ba | b2 | ba2 | b2a | b2a2 |
| b3a | b3a | b3a2 | b | b3a | ba | b2 | ba2 | b2a | b3 | b2a2 | b3a | b4 | b3a2 | b4a | b5 | b4a2 | b5a | b6 | b5a2 | b6a | b6a2 |
| b4 | b4 | b4a | b5 | b4a2 | b5a | b6 | b5a2 | b6a | b | b6a2 | ba | b2 | ba2 | b2a | b3 | b2a2 | b3a | b4 | b3a2 | b4a | b4a2 |
| b3a2 | b3a2 | b3a | b4 | b3a2 | b4a | b5 | b4a2 | b5a | b6 | b5a2 | b6a | b | b6a2 | ba | b2 | ba2 | b2a | b3 | b2a2 | b3a | b3a2 |
| b4a | b4a | b4a2 | b2 | b4a | b2a | b3 | b2a2 | b3a | b4 | b3a2 | b4a | b5 | b4a2 | b5a | b6 | b5a2 | b6a | b | b6a2 | ba | ba2 |
| b5 | b5 | b5a | b6 | b5a2 | b6a | b | b6a2 | ba | b2 | ba2 | b2a | b3 | b2a2 | b3a | b4 | b3a2 | b4a | b5 | b4a2 | b5a | b5a2 |
| b4a2 | b4a2 | b4a | b5 | b4a2 | b5a | b6 | b5a2 | b6a | b | b6a2 | ba | b2 | ba2 | b2a | b3 | b2a2 | b3a | b4 | b3a2 | b4a | b4a2 |
| b5a | b5a | b5a2 | b3 | b5a | b3a | b4 | b3a2 | b4a | b5 | b4a2 | b5a | b6 | b5a2 | b6a | b | b6a2 | ba | b2 | ba2 | b2a | b2a2 |
| b6 | b6 | b6a | b | b6a2 | ba | b2 | ba2 | b2a | b3 | b2a2 | b3a | b4 | b3a2 | b4a | b5 | b4a2 | b5a | b6 | b5a2 | b6a | b6a2 |
| b5a2 | b5a2 | b5a | b6 | b5a2 | b6a | b | b6a2 | ba | b2 | ba2 | b2a | b3 | b2a2 | b3a | b4 | b3a2 | b4a | b5 | b4a2 | b5a | b5a2 |
| b6a | b6a | b6a2 | b4 | b6a | b4a | b5 | b4a2 | b5a | b6 | b5a2 | b6a | b | b6a2 | ba | b2 | ba2 | b2a | b3 | b2a2 | b3a | b3a2 |
| b6a2 | b6a2 | b6a | b | b6a2 | ba | b2 | ba2 | b2a | b3 | b2a2 | b3a | b4 | b3a2 | b4a | b5 | b4a2 | b5a | b6 | b5a2 | b6a | b6a2 |
| Length: | Presentation: | Description: | Related: |
|---|---|---|---|
| 8 | 〈a, b | aaa=ab, bbb=1〉 | Finite non-commutative monoid with 21 elements | 6 isomorphic, 9 anti-isomorphic |
| 8 | 〈a, b | aaa=1, abbb=b〉 | Finite non-commutative monoid with 21 elements | 10 isomorphic, 5 anti-isomorphic |
| 9 | 〈a, b | aaa=ab, bbb=b〉 | Finite non-commutative monoid with 21 elements | 1 anti-isomorphic |
| 9 | 〈a, b | aaa=1, babb=ab〉 | Finite non-commutative monoid with 21 elements | 6 isomorphic |
| 10 | 〈a, b | aaa=aa, bbb=ab〉 | Finite non-commutative monoid with 21 elements | |
| 11 | 〈a, b | aaaaa=b, abbbb=1〉 | Isomorphic to ℤ21 | 13 isomorphic |
| 11 | 〈a, b | bab=aaa, abba=b〉 | Finite non-commutative monoid with 21 elements | |
| 11 | 〈a, b | bab=aaa, bbb=aa〉 | Finite non-commutative monoid with 21 elements | |
| 11 | 〈a, b | aab=ba, ababab=1〉 | Finite non-Abelian group with 21 elements | 1 isomorphic |
| 11 | 〈a, b | aaa=a, ababbb=b〉 | Finite non-commutative monoid with 21 elements | 1 isomorphic |
| 11 | 〈a, b | aba=b, baaaab=a〉 | Finite non-commutative monoid with 21 elements | |
| 11 | 〈a, b | aaa=1, abbab=aba〉 | Finite non-commutative monoid with 21 elements |