Atlas › Modular forms › Weight 4 › Level 206 › 206.4.a › 206.4.a.b

Newform orbit 206.4.a.b

Trace form

The 2 newforms in this orbit are conjugate over $\mathbb{Q}$ ; the sum of their $q$ -expansions is

$2q - 4q^{2} + 2q^{3} + 8q^{4} + 15q^{5} - 4q^{6} - 20q^{7} - 16q^{8} - 52q^{9} - 30q^{10} - 37q^{11} + 8q^{12} - 19q^{13} + 40q^{14} + 15q^{15} + 32q^{16} - 17q^{17} + 104q^{18} + 51q^{19} + 60q^{20} - 20q^{21} + 74q^{22} - 100q^{23} - 16q^{24} + O(q^{25})$

Coefficient field

The coefficients $a_n$ generate $\mathbb{Q}(\sqrt{101})$ . It is generated by the eigenvalue $\alpha$ of $T = T_{3} + T_{5}$ , whose minimal polynomial is

$x^{2} - 17x + 47$

Atkin–Lehner signs

$p$	$w_p$
2	$+1$
103	$-1$

For $p \parallel N$ every form in the orbit has $a_p = -p^{k/2-1} w_p$ . The Fricke sign is $w_N = -1$ , so the sign of the functional equation is $(-1)^{k/2} w_N = -1$ : each L-function in the orbit has odd analytic rank.

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
$\operatorname{tr} a_p$	−4	2	15	−20	−37	−19	−17	51	−100	−150	−176	−426	−360	−64	163	−241	−133	−505	118	629	−453	−53	629	1814	−214

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

Provenance

Stored in the atlas: computed by Sagebrush's modular symbols engine in 0.14 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 engine's checks

dim M^+ at levels [1, 2, 103, 206]: [1, 2, 27, 80] (certified at ell = 2147482501)
T = [(3, 1), (5, 1)]; h of degree 26 = 1 x 26 (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(206, 4)[1]   # 206.4.a.b

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

cargo run --release -p sagebrush-web --example atlas -- 206:4 1000