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
256.1-CMa1
256.1-CMa
$2$
$2$
\(\Q(\sqrt{-1}) \)
$2$
$[0, 1]$
256.1
\( 2^{8} \)
\( 2^{12} \)
$0.71487$
$(a+1)$
0
$\Z/2\Z\oplus\Z/2\Z$
$\textsf{yes}$
$-4$
$\mathrm{U}(1)$
✓
✓
✓
$2$
2Cs
$1$
\( 2 \)
$1$
$6.875185818$
0.859398227
\( 1728 \)
\( \bigl[0\) , \( 0\) , \( 0\) , \( 1\) , \( 0\bigr] \)
${y}^2={x}^{3}+{x}$
256.1-CMa2
256.1-CMa
$2$
$2$
\(\Q(\sqrt{-1}) \)
$2$
$[0, 1]$
256.1
\( 2^{8} \)
\( 2^{18} \)
$0.71487$
$(a+1)$
0
$\Z/4\Z$
$\textsf{yes}$
$-16$
$\mathrm{U}(1)$
✓
✓
✓
$1$
\( 2^{2} \)
$1$
$3.437592909$
0.859398227
\( 287496 \)
\( \bigl[0\) , \( 0\) , \( 0\) , \( 11\) , \( -14 i\bigr] \)
${y}^2={x}^{3}+11{x}-14i$
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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.