Number of cusps of Gamma_1(n)\P_1(Q).

Terms

a(0) =1a(1) =2a(2) =2a(3) =3a(4) =4a(5) =4a(6) =6a(7) =6a(8) =8a(9) =8a(10) =10a(11) =10a(12) =12a(13) =12a(14) =16a(15) =14a(16) =16a(17) =16a(18) =18a(19) =20a(20) =24a(21) =20a(22) =22a(23) =24a(24) =28a(25) =24a(26) =30a(27) =30a(28) =28a(29) =32