Waring problem with the Ramanujan $\tau$-function
  Let $\tau(n)$ be the Ramanujan $\tau$-function. We prove that for any integer $N$ the diophantine equation $$ \sum_{i=1}^{74000}\tau(n_i)=N $$ has a solution in positive integers $n_1, n_2,..., n_{74000}$ satisfying the condition $$ \max_{1\le i\le 74000}n_i\ll |N|^{2/11}+1. $$ We also consider similar questions in the residue ring modulo a large prime $p.$ 
M. Z. Garaev, V. C. Garcia, S. V. Konyagin