Label
Class
Class size
Class degree
Base field
Field degree
Field signature
Conductor
Conductor norm
Discriminant norm
Root analytic conductor
Bad primes
Rank
Torsion
CM
CM
Sato-Tate
$\Q$-curve
Base change
Semistable
Potentially good
Nonmax $\ell$
mod-$\ell$ images
$Ш_{\textrm{an}}$
Tamagawa
Regulator
Period
Leading coeff
j-invariant
Weierstrass coefficients
Weierstrass equation
320.1-a5
320.1-a
$8$
$16$
\(\Q(\sqrt{5}) \)
$2$
$[2, 0]$
320.1
\( 2^{6} \cdot 5 \)
\( 2^{8} \cdot 5^{2} \)
$0.84511$
$(-2a+1), (2)$
0
$\Z/2\Z\oplus\Z/4\Z$
$\textsf{no}$
$\mathrm{SU}(2)$
✓
✓
$2$
2Cs
$1$
\( 2^{2} \)
$1$
$35.25568626$
0.985426388
\( \frac{55296}{5} \)
\( \bigl[0\) , \( 0\) , \( 0\) , \( -2\) , \( 1\bigr] \)
${y}^2={x}^{3}-2{x}+1$
1280.1-a5
1280.1-a
$8$
$16$
\(\Q(\sqrt{5}) \)
$2$
$[2, 0]$
1280.1
\( 2^{8} \cdot 5 \)
\( 2^{8} \cdot 5^{2} \)
$1.19516$
$(-2a+1), (2)$
0
$\Z/2\Z\oplus\Z/2\Z$
$\textsf{no}$
$\mathrm{SU}(2)$
✓
$2$
2Cs
$1$
\( 2 \)
$1$
$23.97511185$
1.340249496
\( \frac{55296}{5} \)
\( \bigl[0\) , \( 0\) , \( 0\) , \( 2 \phi - 4\) , \( -2 \phi + 3\bigr] \)
${y}^2={x}^{3}+\left(2\phi-4\right){x}-2\phi+3$
1280.1-i5
1280.1-i
$8$
$16$
\(\Q(\sqrt{5}) \)
$2$
$[2, 0]$
1280.1
\( 2^{8} \cdot 5 \)
\( 2^{8} \cdot 5^{2} \)
$1.19516$
$(-2a+1), (2)$
$1$
$\Z/2\Z\oplus\Z/2\Z$
$\textsf{no}$
$\mathrm{SU}(2)$
✓
✓
$2$
2Cs
$1$
\( 2 \)
$0.933393502$
$16.30392283$
1.701421401
\( \frac{55296}{5} \)
\( \bigl[0\) , \( 0\) , \( 0\) , \( -2\) , \( -1\bigr] \)
${y}^2={x}^{3}-2{x}-1$
1280.1-j5
1280.1-j
$8$
$16$
\(\Q(\sqrt{5}) \)
$2$
$[2, 0]$
1280.1
\( 2^{8} \cdot 5 \)
\( 2^{8} \cdot 5^{2} \)
$1.19516$
$(-2a+1), (2)$
0
$\Z/2\Z\oplus\Z/2\Z$
$\textsf{no}$
$\mathrm{SU}(2)$
✓
$2$
2Cs
$1$
\( 2 \)
$1$
$23.97511185$
1.340249496
\( \frac{55296}{5} \)
\( \bigl[0\) , \( 0\) , \( 0\) , \( 2 \phi - 4\) , \( 2 \phi - 3\bigr] \)
${y}^2={x}^{3}+\left(2\phi-4\right){x}+2\phi-3$
1600.1-a5
1600.1-a
$8$
$16$
\(\Q(\sqrt{5}) \)
$2$
$[2, 0]$
1600.1
\( 2^{6} \cdot 5^{2} \)
\( 2^{8} \cdot 5^{8} \)
$1.26373$
$(-2a+1), (2)$
0
$\Z/2\Z\oplus\Z/2\Z$
$\textsf{no}$
$\mathrm{SU}(2)$
✓
$2$
2Cs
$1$
\( 2^{3} \)
$1$
$7.291335953$
1.630392283
\( \frac{55296}{5} \)
\( \bigl[0\) , \( 0\) , \( 0\) , \( -10 \phi - 10\) , \( -20 \phi - 15\bigr] \)
${y}^2={x}^{3}+\left(-10\phi-10\right){x}-20\phi-15$
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*The rank, regulator and analytic order of Ш are
not known for all curves in the database; curves for which these are
unknown will not appear in searches specifying one of these
quantities.