Atlas › Modular forms › Weight 2 › Level 213 › 213.2.a › 213.2.a.b

Newform orbit 213.2.a.b

Trace form

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

$2q - 3q^{2} + 2q^{3} + 3q^{4} - 5q^{5} - 3q^{6} - 4q^{7} - 6q^{8} + 2q^{9} + 5q^{10} - 8q^{11} + 3q^{12} - q^{13} + 11q^{14} - 5q^{15} + 13q^{16} - 4q^{17} - 3q^{18} - 8q^{19} - 4q^{21} + 7q^{22} - 3q^{23} - 6q^{24} + O(q^{25})$

Coefficient field

The coefficients $a_n$ generate $\mathbb{Q}(\sqrt{5})$ . It is generated by the eigenvalue $\alpha$ of $T = T_{2} + 3T_{5}$ , whose minimal polynomial is

$x^{2} + 18x + 76$

Atkin–Lehner signs

$p$	$w_p$
3	$-1$
71	$-1$

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
$\operatorname{tr} a_p$	−3	2	−5	−4	−8	−1	−4	−8	−3	3	8	−1	−17	−15	15	9	4	10	−5	2	2	−5	−12	−14	5

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

Provenance

Stored in the atlas: computed by Sagebrush's modular symbols engine in 0.307 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, 3, 71, 213]: [0, 1, 7, 26] (certified at ell = 2147483171)
T = [(2, 1), (5, 3)]; h of degree 11 = 1 x 11 (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(213, 2)[1]   # 213.2.a.b

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

cargo run --release -p sagebrush-web --example atlas -- 213:2 1000