Space of modular forms of level 18, weight 21, and Character 18.d

• Label: 18.21.d
• Level: $18$
• Weight: $21$
• Character orbit: 18.d
• Rep. character: $\chi_{18}(5,\cdot)$
• Character field: $\Q(\zeta_{6})$
• Dimension: $40$
• Newform subspaces: $1$
• Sturm bound: $63$
• Trace bound: $0$

Defining parameters

Level:	\( N \)	\(=\)	\( 18 = 2 \cdot 3^{2} \)
Weight:	\( k \)	\(=\)	\( 21 \)
Character orbit:	\([\chi]\)	\(=\)	18.d (of order \(6\) and degree \(2\))
Character conductor:	\(\operatorname{cond}(\chi)\)	\(=\)	\( 9 \)
Character field:			\(\Q(\zeta_{6})\)
Newform subspaces:			\( 1 \)
Sturm bound:			\(63\)
Trace bound:			\(0\)

Dimensions

The following table gives the dimensions of various subspaces of \(M_{21}(18, [\chi])\).

	Total	New	Old
Modular forms	124	40	84
Cusp forms	116	40	76
Eisenstein series	8	0	8

Trace form

40 * q - 18846 * q^3 + 10485760 * q^4 + 29763918 * q^5 + 102690816 * q^6 + 133479866 * q^7 + 967310598 * q^9 - 35793208728 * q^11 + 26559381504 * q^12 + 39827158550 * q^13 + 187564400640 * q^14 - 965812538286 * q^15 - 5497558138880 * q^16 - 481837940736 * q^18 - 10560819523540 * q^19 + 15604865040384 * q^20 - 64715095872294 * q^21 + 10829007458304 * q^22 - 95164852839678 * q^23 + 18380312543232 * q^24 + 485893942617694 * q^25 - 312810773554224 * q^27 + 139963783970816 * q^28 + 487337329131246 * q^29 - 1016412645851136 * q^30 - 386065992062842 * q^31 + 2417458230482544 * q^33 - 810410730184704 * q^34 + 440007640743936 * q^36 + 7650497672534432 * q^37 - 27431157167935488 * q^38 + 21847743729103830 * q^39 - 76546903885431012 * q^41 - 27408162766282752 * q^42 - 10868849409851092 * q^43 - 151711625857797018 * q^45 + 13732137981788160 * q^46 + 220882065588142506 * q^47 + 19105114044235776 * q^48 - 201918836583922386 * q^49 + 84434006357065728 * q^50 - 112944490440784866 * q^51 - 20880901301862400 * q^52 - 907744599291211776 * q^54 - 689556443803109316 * q^55 + 98337764482744320 * q^56 + 524175567253271298 * q^57 + 289875600503808000 * q^58 - 4671324023815652220 * q^59 + 999198431835586560 * q^60 - 608513692992272866 * q^61 - 6762387225153657666 * q^63 - 5764607523034234880 * q^64 + 4959300225343873626 * q^65 + 7794266473078972416 * q^66 - 2581864509390888904 * q^67 - 5171455594224156672 * q^68 - 715869785458553814 * q^69 - 584784912675889152 * q^70 - 3996696553325592576 * q^72 + 15022099327729072004 * q^73 + 7089371473773993984 * q^74 + 10151951406704814570 * q^75 - 2768455473178869760 * q^76 - 30865724759591472834 * q^77 + 14351578809049718784 * q^78 + 18532232803602736754 * q^79 - 14205809545514203338 * q^81 - 35601230743051272192 * q^82 + 54829678294093455594 * q^83 - 34962890419605602304 * q^84 + 43688870161052471388 * q^85 + 47393791396458614784 * q^86 + 23116374920781444150 * q^87 - 5677518662299287552 * q^88 + 122957322600559583232 * q^90 - 35182774173576758996 * q^91 - 49893790365609099264 * q^92 + 30021582829442833806 * q^93 + 19892618446780047360 * q^94 + 332020921293200455200 * q^95 - 18590859261785407488 * q^96 - 66463398176406835216 * q^97 + 525216922205664004722 * q^99

Decomposition of \(S_{21}^{\mathrm{new}}(18, [\chi])\) into newform subspaces

Label	Level	Weight	Char	Prim	Char order	Dim	Rel. Dim	$A$	Field	CM	Self-dual	Twist minimal	Largest	Maximal	Minimal twist	Inner twists	Rank*	Traces				Coefficient ring index	Sato-Tate	$q$-expansion
																		$a_{2}$	$a_{3}$	$a_{5}$	$a_{7}$
18.21.d.a	$18$	$21$	18.d	9.d	$6$	$40$	$20$	$45.632$		None		✓	✓	✓	18.21.d.a	$2$	$0$	\(0\)	\(-18846\)	\(29763918\)	\(133479866\)		$\mathrm{SU}(2)[C_{6}]$

Decomposition of \(S_{21}^{\mathrm{old}}(18, [\chi])\) into lower level spaces

\( S_{21}^{\mathrm{old}}(18, [\chi]) \simeq \) \(S_{21}^{\mathrm{new}}(9, [\chi])\)\(^{\oplus 2}\)