摘要

Let L(sym(j) f, s) be the j th symmetric power L- function attached to a holomorphic Hecke eigencuspform f (z) for the full modular group, and lambda(symj) (f) (n) denote its nth coefficient. In this paper we are able to prove that integral(x)(1) vertical bar Sigma(n <= y) lambda(3)(sym)f (n)vertical bar(2) dy = O(x(2)), integral(x)(1) vertical bar Sigma(n <= y) lambda(4)(sym)(f) (n)vertical bar(2) dy = O(x(11/5) log x).