MathDB
wonky sequence

Source: ICMC 2021 Round 2 P2

December 12, 2021
number theoryICMCcollege contestsmod p

Problem Statement

Let p>3p > 3 be a prime number. A sequence of p1p-1 integers a1,a2,,ap1a_1,a_2, \dots, a_{p-1} is called wonky if they are distinct modulo pp and aiai+2≢ai+12(modp)a_ia_{i+2} \not\equiv a_{i+1}^2 \pmod p for all i{1,2,,p1}i \in \{1, 2, \dots, p-1\}, where ap=a1a_p = a_1 and ap+1=a2a_{p+1} = a_2. Does there always exist a wonky sequence such that a1a2,a1a2+a2a3,,a1a2++ap1a1,a_1a_2, \qquad a_1a_2+a_2a_3, \qquad \dots, \qquad a_1a_2+\cdots +a_{p-1}a_1, are all distinct modulo pp?
Proposed by Harun Khan