Explicit bounds for sums of squares
Explicit bounds for sums of squares
For an even integer k, let r 2k (n) be the number of representations of n as a sum of 2k squares.The quantity r 2k (n) is approximated by the classical singular series ρ 2k (n) n k-1 .Deligne's bound on the Fourier coefficients of Hecke eigenforms gives2 ).We determine …