Interesting identities involving weighted representations of integers as sums of arbitrarily many squares
arXiv:1904.06794 · doi:10.1073/pnas.1906632116
Abstract
In this paper, we obtain formulas for the number of representations of positive integers as sums of arbitrarily many squares (and other polygonal numbers) with a certain natural weighting. The resulting weighted sums give Fourier coefficients of weight two quasimodular forms.