Atlas › Modular forms › Weight 2 › Level 948 › 948.2.a › 948.2.a.c

Newform orbit 948.2.a.c

$q$ -expansion

$q + q^{3} - q^{7} + q^{9} + 3q^{11} + 5q^{13} - 3q^{17} + 2q^{19} - q^{21} - 3q^{23} + O(q^{25})$

Coefficient field

The coefficients $a_n$ generate $\mathbb{Q}$ . The eigenvalue of $T = T_{5} + 3T_{7} + 5T_{11} + 7T_{13} + 9T_{17}$ is a root of

$x - 20$

Atkin–Lehner signs

$p$	$w_p$
2	— ( $2^2 \mid 948$ )
3	$-1$
79	$-1$

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 948.c (Cremona's 948c). Its optimal curve 948c1 is

$y^2 = x^3 + x^2 + 12x + 36$

of rank 0 with torsion of order 3. 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	0	−1	3	5	−3	2	−3	9	2	8	6	11	−6	6	−6	−10	8	−12	11	1	−3	−12	−1

$\operatorname{tr} a_n$ 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 948, against the semicircle $\tfrac{2}{\pi}\sqrt{1 - x^2}$ :

Provenance

Stored in the atlas: computed by Sagebrush's modular symbols engine in 0.615 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, 79, 158, 237, 316, 474, 948]: [0, 1, 1, 2, 3, 5, 7, 22, 28, 43, 84, 166] (certified at ell = 2147483053)
T = [(5, 1), (7, 3), (11, 5), (13, 7), (17, 9)]; h of degree 14 = 1 x 14 (phi(ord eps) x dim S_k^new); 4 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(948, 2)[2]   # 948.2.a.c

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

cargo run --release -p sagebrush-web --example atlas -- 948:2 1000