MathDB
Arithmetic sequence

Source: Mathematics and Youth Magazine (vietnam)

September 16, 2020
number theoryarithmetic sequence

Problem Statement

The sequence (an)\left(a_n \right) is defined by a1=1, a2=2a_1=1, \ a_2=2 and an+2=2an+1pan, n1,a_{n+2} = 2a_{n+1}-pa_n, \ \forall n \ge 1, for some prime p.p. Find all pp for which there exists mm such that am=3.a_m=-3.