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Numbers N such that the modular curve X_0(N) is hyperelliptic.
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%I #15 Oct 18 2016 11:59:04

%S 22,23,26,28,29,30,31,33,35,37,39,40,41,46,47,48,50,59,71

%N Numbers N such that the modular curve X_0(N) is hyperelliptic.

%C "The only case where the hyperelliptic involution is not defined by an element of SL(2, R) is N=37."

%C "For N = 40, 48 the hyperelliptic involution v is not of Atkin-Lehner type. The remaining sixteen values are listed in the table below, together with their genera and hyperelliptic involutions v." (see Ogg link)

%C n N g v

%C 1 22 2 11

%C 2 23 2 23

%C 3 26 2 26

%C 4 28 2 7

%C 5 29 2 29

%C 6 30 3 15

%C 7 31 2 31

%C 8 33 3 11

%C 9 35 3 35

%C 10 39 3 39

%C 11 41 3 41

%C 12 46 5 23

%C 13 47 4 47

%C 14 50 2 50

%C 15 59 5 59

%C 16 71 6 71

%H Andrew P. Ogg, <a href="http://www.numdam.org/item?id=BSMF_1974__102__449_0">Hyperelliptic modular curves</a>, Bulletin de la S. M. F., 102 (1974), p. 449-462.

%Y Cf. A001617, A260990.

%K nonn,fini,full

%O 1,1

%A _Gheorghe Coserea_, Oct 17 2016