Divisor problems for restricted Fourier coefficients of modular forms
摘要
Let d(n) be the number of divisors of n. We investigate the average value of d(af(p))r for r a positive integer and af(p) the p-th Fourier coefficient of a cuspidal eigenform f having integral Fourier coefficients, where p is a prime subject to a constraint on the angle associated with the normalized Fourier coefficient.