MathDB

Problem 1

Part of 2022 Nigerian MO round 3

Problems(1)

Permutation sequence

Source: 2022 Nigerian MO Round 3/Problem 1

5/2/2022
Integer sequence (xn)(x_{n}) is defined as follows; x1=1x_{1} = 1, and for each integer n≥1n \geq 1, xn+1x_{n+1} is equal to the largest number that can be obtained by permutation of the digits of xn+2x_{n}+2. Find the smallest nn for which the decimal representation of xnx_{n} contains exactly 20222022 digits
Sequencealgebra