Atlas › Modular forms › Weight 2 › Level 988 › 988.2.a › 988.2.a.d

Newform orbit 988.2.a.d

$q$ -expansion

$q + 2q^{3} + 4q^{5} + 2q^{7} + q^{9} - q^{13} + 8q^{15} - 3q^{17} - q^{19} + 4q^{21} + 3q^{23} + O(q^{25})$

Coefficient field

The coefficients $a_n$ generate $\mathbb{Q}$ . The eigenvalue of $T = T_{3} + 2T_{5} + 3T_{7} + 4T_{11} + 5T_{17} + 6T_{23} + 7T_{29} + 8T_{31}$ is a root of

$x + 83$

Atkin–Lehner signs

$p$	$w_p$
2	— ( $2^2 \mid 988$ )
13	$+1$
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 988.d (Cremona's 988a). Its optimal curve 988a1 is

$y^2 = x^3 - x^2 + 114x - 247$

of rank 0 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	2	4	2	0	−1	−3	−1	3	−2	−11	−5	−5	11	−6	−14	11	7	−7	12	4	−2	−2	2	17

$\operatorname{tr} a_n$ 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 988, against the semicircle $\tfrac{2}{\pi}\sqrt{1 - x^2}$ :

Provenance

Stored in the atlas: computed by Sagebrush's modular symbols engine in 0.659 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, 4, 13, 19, 26, 38, 52, 76, 247, 494, 988]: [0, 1, 2, 1, 2, 5, 7, 10, 13, 24, 74, 146] (certified at ell = 2147483629)
T = [(3, 1), (5, 2), (7, 3), (11, 4), (17, 5), (23, 6), (29, 7), (31, 8)]; h of degree 18 = 1 x 18 (phi(ord eps) x dim S_k^new); 5 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(988, 2)[3]   # 988.2.a.d

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

cargo run --release -p sagebrush-web --example atlas -- 988:2 1000