Total number of congruence subgroups of PSL(2,Z) of genus n.

Terms

a(0) =1116a(1) =2801a(2) =4107a(3) =6513a(4) =7257a(5) =9386a(6) =10416a(7) =18191a(8) =13726a(9) =21014a(10) =15622a(11) =27466a(12) =18095a(13) =33241a(14) =22871a(15) =40880a(16) =30809a(17) =54794a(18) =24935a(19) =60648a(20) =31137a(21) =66841a(22) =36135a(23) =59450a(24) =42289