MathDB
I_n is set of solutions x^2 −2xy+y^2−4^n = 0 , where y \in I_{n-1}

Source: ITAMO 1987 p4

February 2, 2020
equationSetsalgebra

Problem Statement

Given I0={1,1}I_0 = \{-1,1\}, define InI_n recurrently as the set of solutions xx of the equations x22xy+y24n=0x^2 -2xy+y^2- 4^n = 0, where yy ranges over all elements of In1I_{n-1}. Determine the union of the sets InI_n over all nonnegative integers nn.