Atlas › Modular forms › Weight 2 › Level 228 › 228.2.a › 228.2.a.a

Newform orbit 228.2.a.a

$q$ -expansion

$q - q^{3} - 3q^{5} + q^{7} + q^{9} - 5q^{11} - 6q^{13} + 3q^{15} - 5q^{17} + q^{19} - q^{21} + 4q^{23} + O(q^{25})$

Coefficient field

The coefficients $a_n$ generate $\mathbb{Q}$ . The eigenvalue of $T = T_{5} + 3T_{7} + 5T_{13} + 7T_{17} + 9T_{23}$ is a root of

$x + 29$

Atkin–Lehner signs

$p$	$w_p$
2	— ( $2^2 \mid 228$ )
3	$+1$
19	$-1$

For $p \parallel N$ every form in the orbit has $a_p = -p^{k/2-1} w_p$ .

Elliptic curve

By modularity this newform is the one attached to the isogeny class 228.a (Cremona's 228b). Its optimal curve 228b1 is

$y^2 = x^3 - x^2 + 3x + 9$

of rank 1 with torsion of order 1. Its $a_p$ , computed by Sagebrush's point-counting engine, equal the newform's for every prime $p < 1000$ .

Traces of Hecke eigenvalues

$p$	2	3	5	7	11	13	17	19	23	29	31	37	41	43	47	53	59	61	67	71	73	79	83	89	97
$\operatorname{tr} a_p$	0	−1	−3	1	−5	−6	−5	1	4	6	6	−8	−8	9	1	2	−8	11	0	−4	−11	−8	−4	10	−10

$\operatorname{tr} a_n$ for every $n \le 1000$ is in the JSON.

Sato–Tate

The normalized $a_p / 2p^{1/2}$ for the primes $p < 1000$ not dividing 228, against the semicircle $\tfrac{2}{\pi}\sqrt{1 - x^2}$ :

Provenance

Stored in the atlas: computed by Sagebrush's modular symbols engine in 0.243 s (one thread) and proven: the dimensions are certified, and the characteristic polynomial of $T$ over $\mathbb{Z}$ is reconstructed by CRT past a rigorous coefficient bound. The label, dimension and $\operatorname{tr} a_p$ for every $p < 1000$ equal LMFDB's.

The engine's checks

dim M^+ at levels [1, 2, 3, 4, 6, 12, 19, 38, 57, 76, 114, 228]: [0, 1, 1, 2, 3, 5, 2, 7, 8, 13, 24, 46] (certified at ell = 2147483647)
T = [(5, 1), (7, 3), (13, 5), (17, 7), (23, 9)]; h of degree 4 = 1 x 4 (phi(ord eps) x dim S_k^new); 2 primes, 0 rejected

Open in the notebook · JSON · stored data

Recompute it yourself

In Sage mode at sagebrush.space (or npx sagebrush --sage):

newform_orbits(228, 2)[0]   # 228.2.a.a

With the Rust engine (source), in engine/:

cargo run --release -p sagebrush-web --example atlas -- 228:2 1000