## The modular curve $X_{308}$

Curve name $X_{308}$
Index $48$
Level $16$
Genus $1$
Does the subgroup contain $-I$? Yes
Generating matrices $\left[ \begin{matrix} 9 & 4 \\ 0 & 1 \end{matrix}\right], \left[ \begin{matrix} 5 & 14 \\ 4 & 1 \end{matrix}\right], \left[ \begin{matrix} 15 & 9 \\ 0 & 1 \end{matrix}\right], \left[ \begin{matrix} 15 & 14 \\ 2 & 1 \end{matrix}\right]$
Images in lower levels
 Level Index of image Corresponding curve $2$ $3$ $X_{6}$ $4$ $6$ $X_{11}$ $8$ $24$ $X_{97}$
Meaning/Special name
Chosen covering $X_{97}$
Curves that $X_{308}$ minimally covers $X_{97}$, $X_{107}$, $X_{165}$
Curves that minimally cover $X_{308}$ $X_{632}$, $X_{634}$, $X_{672}$, $X_{673}$
Curves that minimally cover $X_{308}$ and have infinitely many rational points.
Model $y^2 = x^3 + x^2 - 3x + 1$
Info about rational points $X_{308}(\mathbb{Q}) \cong \mathbb{Z}/2\mathbb{Z} \times\mathbb{Z}$
Comments on finding rational points None
Elliptic curve whose $2$-adic image is the subgroup $y^2 = x^3 - 36892805x + 85720848400$, with conductor $173600$
Generic density of odd order reductions $42979/172032$