C7:C3 SmallGroup(21, 1)

[21 8 3 2]: [f2^2, f1*f2^2, f2^3, f2^4, f2^5, f1^2*f2^4, f1*f2^6, f1^2*f2^6]
            [6, 8, 9, 12, 15, 16, 20, 21]

[21 8 4 2]: [f2, f2^2, f1*f2^2, f2^5, f1^2*f2^4, f2^6, f1*f2^6, f1^2*f2^6]
            [3, 6, 8, 15, 16, 18, 20, 21]

[21 12 7 5]: [f1, f1^2, f1*f2, f1^2*f2, f2^3, f1^2*f2^2, f1*f2^3, f2^4, f1^2*f2^3, f1*f2^4, f1*f2^5, f1^2*f2^5]
             [2, 4, 5, 7, 9, 10, 11, 12, 13, 14, 17, 19]

[21 12 7 6]: [f1, f2, f1^2, f1*f2, f2^2, f1^2*f2, f1^2*f2^2, f1*f2^3, f1^2*f2^3, f2^5, f1*f2^5, f2^6]
             [2, 3, 4, 5, 6, 7, 10, 11, 13, 15, 17, 18]

[21 12 7 6]: [f1, f2, f1^2, f1*f2, f2^2, f2^3, f1^2*f2^2, f1*f2^3, f2^4, f1^2*f2^3, f2^5, f2^6]
             [2, 3, 4, 5, 6, 9, 10, 11, 12, 13, 15, 18]