Rényi's Polynomial

Rényi's polynomial is the polynomial

(Rényi 1947, Coppersmith and Davenport 1991) that has 29 terms and whose square has 28, making it a sparse polynomial square.

REFERENCES:

Coppersmith, D. and Davenport, J. "Polynomials Whose Powers Are Sparse." Acta Arith. 58, 79-87, 1991.

Rényi, A. "On the Minimal Number of Terms in the Square of a Polynomial." Acta Math. Hungar. 1, 30-34, 1947. Reprinted in Selected Papers of Alfred Rényi, Vol. 1. Budapest, pp. 44-47, 1976.