Describe a sequence, discover a formula and verify it. Begin at the first unfamiliar idea; the prerequisite links help you find a shorter route. You can open any lesson.
- R01
Recursive sequences
Compute terms and explain why initial conditions matter.
Inside: Recursive sequences and initial conditions · Recursive versus explicit descriptions
- R02
Classifying recurrence relations
Classify a recurrence to select an appropriate method.
Inside: Order and linearity · Homogeneous and non-homogeneous recurrences
- R03
First-order linear recurrences
Transform a first-order recurrence and verify its explicit formula.
Inside: Arithmetic and geometric cases · Shifting a fixed point · Telescoping and variable forcing
- R04
Nonlinear recurrences and substitutions
Find a substitution suggested by the recurrence rather than guessing at random.
Inside: Reciprocal substitutions · Factoring a recurrence · Invariants and domain restrictions
- R05
Second-order linear recurrences
Solve a second-order recurrence and justify the resulting expression.
Inside: Characteristic roots · Distinct and repeated roots · Initial-value verification
- R06
Higher-order linear recurrences
Explain how the order and root multiplicities control the general form.
Inside: Higher-order recurrences · Repeated roots and enough initial conditions
- R07
Non-homogeneous recurrences
Choose a valid particular form and adjust it when it overlaps the homogeneous part.
Inside: Particular plus homogeneous solutions · Resonance · Verifying the combined solution
These original lessons introduce the methods and give practice with solutions. A single short session is not a full assessment of Olympiad readiness. Build depth through the written challenges and your country’s official past papers.