Atlas › Modular forms › Weight 2 › Level 721 › 721.2.a › 721.2.a.c

Newform orbit 721.2.a.c

Trace form

The 7 newforms in this orbit are conjugate over $\mathbb{Q}$ ; the sum of their $q$ -expansions is

$7q - 3q^{2} - 2q^{3} + 15q^{4} - 11q^{5} - 10q^{6} + 7q^{7} - 9q^{8} - 5q^{9} - 12q^{11} - 8q^{12} - 2q^{13} - 3q^{14} + 6q^{15} - 5q^{16} - 19q^{17} + 12q^{18} + q^{19} - 26q^{20} - 2q^{21} + 2q^{22} - 11q^{23} - 4q^{24} + O(q^{25})$

Coefficient field

The coefficients $a_n$ generate a number field of degree 7. It is generated by the eigenvalue $\alpha$ of $T = T_{2} + T_{3}$ , whose minimal polynomial is

$x^{7} + 5x^{6} - 21x^{4} - 20x^{3} - x^{2} + 4x + 1$

Atkin–Lehner signs

$p$	$w_p$
7	$-1$
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
$\operatorname{tr} a_p$	−3	−2	−11	7	−12	−2	−19	1	−11	−4	6	−1	−31	10	−18	0	−24	−7	4	−18	−8	−15	6	−20	−26

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

Provenance

Stored in the atlas: computed by Sagebrush's modular symbols engine in 0.226 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, 7, 103, 721]: [0, 1, 9, 70] (certified at ell = 2147482501)
T = [(2, 1), (3, 1)]; h of degree 51 = 1 x 51 (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(721, 2)[2]   # 721.2.a.c

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

cargo run --release -p sagebrush-web --example atlas -- 721:2 1000