Mathematical Journal of Okayama University 59巻 1号
2017-01 発行

Evaluation of convolution sums and some remarks on cusp forms of weight 4 and level 12

Ramakrishhan, B. Harish-Chandra Research Institute
Sahu, Brundaban School of Mathematical Sciences National Institute of Science Education and Research
Publication Date
In this note, we evaluate certain convolution sums and make some remarks about the Fourier coefficients of cusp forms of weight 4 for Γ0(12). We express the normalized newform of weight 4 on Γ0(12) as a linear combination of the (quasimodular) Eisenstein series (of weight 2) E2(dz), d|12 and their derivatives. Now, by comparing the work of Alaca-Alaca-Williams [1] with our results, as a consequence, we express the coefficients c1,12(n) and c3,4(n) that appear in [1, Eqs.(2.7) and (2.12)] in terms of linear combination of the Fourier coefficients of newforms of weight 4 on Γ0(6) and Γ0(12). The properties of c1,12(n) and c3,4(n) that are derived in [1] now follow from the properties of the Fourier coefficients of the newforms mentioned above. We also express the newforms as a linear combination of certain eta-quotients and obtain an identity involving eta-quotients.
convolution sums of the divisor function
Fourier coeffificients
newforms of integral weight