List of quotient singularities with index 20

40 basic regular quotient singularity types and 52 irregular quotient singularity types

Singularity type Index
[40] 20
[23, 7] 20
[27, 3] 20
[2, 11, 2] 20
[3, 14, 3] 20
[7, 6, 7] 20
[7, 10, 3] 20
[22, 6, 2] 20
[3, 9, 6, 2] 20
[7, 5, 6, 2] 20
[2, 6, 4, 6, 2] 20
[8, 2, 2, 3, 2] 20
[23, 2, 2, 2, 3] 20
[3, 10, 2, 2, 2, 3] 20
[7, 6, 2, 2, 2, 3] 20
[2, 7, 2, 2, 2, 3, 2] 20
[2, 8, 2, 2, 2, 2, 2] 20
[3, 2, 2, 2, 5, 6, 2] 20
[3, 2, 3, 2, 2, 2, 2] 20
[22, 2, 2, 2, 2, 3, 2] 20
[22, 3, 2, 2, 2, 2, 2] 20
[3, 2, 2, 3, 2, 2, 3, 2] 20
[3, 9, 2, 2, 2, 2, 3, 2] 20
[3, 9, 3, 2, 2, 2, 2, 2] 20
[7, 5, 2, 2, 2, 2, 3, 2] 20
[7, 5, 3, 2, 2, 2, 2, 2] 20
[2, 6, 4, 2, 2, 2, 2, 3, 2] 20
[2, 6, 4, 3, 2, 2, 2, 2, 2] 20
[3, 2, 2, 2, 6, 2, 2, 2, 3] 20
[2, 2, 2, 2, 2, 5, 2, 2, 2, 2, 2] 20
[2, 3, 2, 2, 2, 3, 2, 2, 2, 3, 2] 20
[2, 3, 2, 2, 2, 4, 2, 2, 2, 2, 2] 20
[3, 2, 2, 2, 5, 2, 2, 2, 2, 3, 2] 20
[3, 2, 2, 2, 5, 3, 2, 2, 2, 2, 2] 20
[2, 2, 2, 2, 2, 3, 4, 3, 2, 2, 2, 2, 2] 20
[2, 3, 2, 2, 2, 2, 4, 2, 2, 2, 2, 3, 2] 20
[2, 3, 2, 2, 2, 2, 4, 3, 2, 2, 2, 2, 2] 20
[4, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2] 20
[8, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2] 20
[2, 7, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2] 20
[22, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2] 20
[3, 2, 2, 3, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2] 20
[3, 9, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2] 20
[7, 5, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2] 20
[2, 6, 4, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2] 20
[2, 2, 2, 2, 2, 4, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2] 20
[2, 3, 2, 2, 2, 3, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2] 20
[3, 2, 2, 2, 5, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2] 20
[2, 2, 2, 2, 2, 3, 4, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2] 20
[2, 3, 2, 2, 2, 2, 4, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2] 20
[2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 3, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2] 20
[2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 4, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2] 20
Basic singularity type Second singularity type Third singularity type Index
[21, 21] [21, 2, 21] [21, 2, 2, 21] 20
[21, 4, 7] [21, 2, 4, 7] [21, 2, 2, 4, 7] 20
[21, 8, 3] [21, 2, 8, 3] [21, 2, 2, 8, 3] 20
[2, [2], [2], [11]] [2, [2], [2], [2, 11]] [2, [2], [2], [2, 2, 11]] 20
[3, 8, 8, 3] [3, 8, 2, 8, 3] [3, 8, 2, 2, 8, 3] 20
[7, 4, 4, 7] [7, 4, 2, 4, 7] [7, 4, 2, 2, 4, 7] 20
[7, 4, 8, 3] [7, 4, 2, 8, 3] [7, 4, 2, 2, 8, 3] 20
[21, 3, 6, 2] [21, 2, 3, 6, 2] [21, 2, 2, 3, 6, 2] 20
[3, 8, 3, 6, 2] [3, 8, 2, 3, 6, 2] [3, 8, 2, 2, 3, 6, 2] 20
[3, [2], [2], [2, 4]] [2, [2], [2], [3, 2, 4]] [2, [2], [2], [2, 3, 2, 4]] 20
[5, [2], [2], [2, 2]] [2, [2], [2], [5, 2, 2]] [2, [2], [2], [2, 5, 2, 2]] 20
[7, 4, 3, 6, 2] [7, 4, 2, 3, 6, 2] [7, 4, 2, 2, 3, 6, 2] 20
[2, 6, 3, 3, 6, 2] [2, 6, 3, 2, 3, 6, 2] [2, 6, 3, 2, 2, 3, 6, 2] 20
[21, 4, 2, 2, 2, 3] [21, 2, 4, 2, 2, 2, 3] [21, 2, 2, 4, 2, 2, 2, 3] 20
[3, 8, 4, 2, 2, 2, 3] [3, 8, 2, 4, 2, 2, 2, 3] [3, 8, 2, 2, 4, 2, 2, 2, 3] 20
[7, 4, 4, 2, 2, 2, 3] [7, 4, 2, 4, 2, 2, 2, 3] [7, 4, 2, 2, 4, 2, 2, 2, 3] 20
[3, 2, 2, 2, 4, 3, 6, 2] [3, 2, 2, 2, 4, 2, 3, 6, 2] [3, 2, 2, 2, 4, 2, 2, 3, 6, 2] 20
[21, 3, 2, 2, 2, 2, 3, 2] [21, 2, 3, 2, 2, 2, 2, 3, 2] [21, 2, 2, 3, 2, 2, 2, 2, 3, 2] 20
[21, 3, 3, 2, 2, 2, 2, 2] [21, 2, 3, 3, 2, 2, 2, 2, 2] [21, 2, 2, 3, 3, 2, 2, 2, 2, 2] 20
[3, 8, 3, 2, 2, 2, 2, 3, 2] [3, 8, 2, 3, 2, 2, 2, 2, 3, 2] [3, 8, 2, 2, 3, 2, 2, 2, 2, 3, 2] 20
[3, 8, 3, 3, 2, 2, 2, 2, 2] [3, 8, 2, 3, 3, 2, 2, 2, 2, 2] [3, 8, 2, 2, 3, 3, 2, 2, 2, 2, 2] 20
[7, 4, 3, 2, 2, 2, 2, 3, 2] [7, 4, 2, 3, 2, 2, 2, 2, 3, 2] [7, 4, 2, 2, 3, 2, 2, 2, 2, 3, 2] 20
[7, 4, 3, 3, 2, 2, 2, 2, 2] [7, 4, 2, 3, 3, 2, 2, 2, 2, 2] [7, 4, 2, 2, 3, 3, 2, 2, 2, 2, 2] 20
[2, 6, 3, 3, 2, 2, 2, 2, 3, 2] [2, 6, 3, 2, 3, 2, 2, 2, 2, 3, 2] [2, 6, 3, 2, 2, 3, 2, 2, 2, 2, 3, 2] 20
[2, 6, 3, 3, 3, 2, 2, 2, 2, 2] [2, 6, 3, 2, 3, 3, 2, 2, 2, 2, 2] [2, 6, 3, 2, 2, 3, 3, 2, 2, 2, 2, 2] 20
[3, 2, 2, 2, 4, 4, 2, 2, 2, 3] [3, 2, 2, 2, 4, 2, 4, 2, 2, 2, 3] [3, 2, 2, 2, 4, 2, 2, 4, 2, 2, 2, 3] 20
[3, [2], [2], [2, 2, 2, 2, 2, 2, 2, 2]] [2, [2], [2], [3, 2, 2, 2, 2, 2, 2, 2, 2]] [2, [2], [2], [2, 3, 2, 2, 2, 2, 2, 2, 2, 2]] 20
[3, 2, 2, 2, 4, 3, 2, 2, 2, 2, 3, 2] [3, 2, 2, 2, 4, 2, 3, 2, 2, 2, 2, 3, 2] [3, 2, 2, 2, 4, 2, 2, 3, 2, 2, 2, 2, 3, 2] 20
[3, 2, 2, 2, 4, 3, 3, 2, 2, 2, 2, 2] [3, 2, 2, 2, 4, 2, 3, 3, 2, 2, 2, 2, 2] [3, 2, 2, 2, 4, 2, 2, 3, 3, 2, 2, 2, 2, 2] 20
[2, 2, 2, 2, 2, 3, 3, 3, 3, 2, 2, 2, 2, 2] [2, 2, 2, 2, 2, 3, 3, 2, 3, 3, 2, 2, 2, 2, 2] [2, 2, 2, 2, 2, 3, 3, 2, 2, 3, 3, 2, 2, 2, 2, 2] 20
[2, 3, 2, 2, 2, 2, 3, 3, 2, 2, 2, 2, 3, 2] [2, 3, 2, 2, 2, 2, 3, 2, 3, 2, 2, 2, 2, 3, 2] [2, 3, 2, 2, 2, 2, 3, 2, 2, 3, 2, 2, 2, 2, 3, 2] 20
[2, 3, 2, 2, 2, 2, 3, 3, 3, 2, 2, 2, 2, 2] [2, 3, 2, 2, 2, 2, 3, 2, 3, 3, 2, 2, 2, 2, 2] [2, 3, 2, 2, 2, 2, 3, 2, 2, 3, 3, 2, 2, 2, 2, 2] 20
[21, 3, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2] [21, 2, 3, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2] [21, 2, 2, 3, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2] 20
[3, 8, 3, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2] [3, 8, 2, 3, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2] [3, 8, 2, 2, 3, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2] 20
[7, 4, 3, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2] [7, 4, 2, 3, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2] [7, 4, 2, 2, 3, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2] 20
[2, 6, 3, 3, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2] [2, 6, 3, 2, 3, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2] [2, 6, 3, 2, 2, 3, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2] 20
[3, 2, 2, 2, 4, 3, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2] [3, 2, 2, 2, 4, 2, 3, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2] [3, 2, 2, 2, 4, 2, 2, 3, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2] 20
[2, 2, 2, 2, 2, 3, 3, 3, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2] [2, 2, 2, 2, 2, 3, 3, 2, 3, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2] [2, 2, 2, 2, 2, 3, 3, 2, 2, 3, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2] 20
[2, 3, 2, 2, 2, 2, 3, 3, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2] [2, 3, 2, 2, 2, 2, 3, 2, 3, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2] [2, 3, 2, 2, 2, 2, 3, 2, 2, 3, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2] 20
[2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 3, 3, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2] [2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 3, 2, 3, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2] [2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 3, 2, 2, 3, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2] 20

Reference: R. Blache, "Two aspects of log terminal surface singularities", Abh. Math. Sem. Univ. Hamburg 64 (1994), 59-87