Question 61
Find all sequences $(a_n)$ of positive integers satisfying the equality $a_n = a_{n-1} + a_{n+1}$
a) for all $n \ge 2$;
b) for all $n \ge 3$.
a) for all $n \ge 2$;
b) for all $n \ge 3$.
MathNet 2014 Question 61
Math Olympiad Vault · MathNet 2014