Atlas › Modular forms › Weight 2 › Level 836 › 836.2.a › 836.2.a.a

Newform orbit 836.2.a.a

$q$ -expansion

$q - q^{3} + q^{5} - 2q^{9} - q^{11} - 2q^{13} - q^{15} - 4q^{17} + q^{19} + q^{23} + O(q^{25})$

Coefficient field

The coefficients $a_n$ generate $\mathbb{Q}$ . The eigenvalue of $T = T_{3} + 3T_{5} + 5T_{7} + 7T_{17} + 9T_{23} + 11T_{29}$ is a root of

$x + 39$

Atkin–Lehner signs

$p$	$w_p$
2	— ( $2^2 \mid 836$ )
11	$+1$
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 836.a (Cremona's 836a). Its optimal curve 836a1 is

$y^2 = x^3 - x^2 - 5x - 47$

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	1	0	−1	−2	−4	1	1	−2	−5	−3	0	2	0	−10	−3	−6	−3	5	0	−4	−4	1	−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 836, against the semicircle $\tfrac{2}{\pi}\sqrt{1 - x^2}$ :

Provenance

Stored in the atlas: computed by Sagebrush's modular symbols engine in 0.462 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, 11, 19, 22, 38, 44, 76, 209, 418, 836]: [0, 1, 2, 2, 2, 5, 7, 9, 13, 22, 64, 126] (certified at ell = 2147482801)
T = [(3, 1), (5, 3), (7, 5), (17, 7), (23, 9), (29, 11)]; h of degree 16 = 1 x 16 (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(836, 2)[0]   # 836.2.a.a

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

cargo run --release -p sagebrush-web --example atlas -- 836:2 1000