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A360410
Number of passports of index n subgroups in PSL_2 (ZZ).
0
1, 1, 2, 2, 1, 8, 4, 5, 12, 12, 7, 48, 24, 35, 75, 80, 37, 269, 114, 193, 404, 359, 174, 1357, 519, 722, 1664, 1784, 776, 4995, 2054
OFFSET
1,3
COMMENTS
The passports are defined as the conjugacy classes of index n subgroups in PSL_2 (ZZ) modulo the ramification degrees of the covering maps and the monodromy groups.
LINKS
D. Berghaus, H. Monien and D. Radchenko, A Database of Modular Forms on Noncongruence Subgroups, arXiv:2301.02135 [math.NT], 2023.
D. Berghaus, H. Monien and D. Radchenko, A database of subgroups of PSL(2,ℤ) (2023).
CROSSREFS
Sequence in context: A357553 A246745 A111540 * A346709 A096440 A181738
KEYWORD
nonn,more
AUTHOR
David Berghaus, Feb 06 2023
EXTENSIONS
Corrected by David Berghaus, Sep 02 2023
STATUS
approved