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Calcimator

Recurrence Relation Calculator

Solve linear recurrence relations a_n = p*a_{n-1} + q*a_{n-2} with given initial conditions.

Inputs

Results

a(n) Value

55

Closed-Form Estimate55
How to Use This Calculator
  1. Enter the initial values a0 and a1 for the two-term recurrence.
  2. Set Coefficient p (for a_{n-1}) and Coefficient q (for a_{n-2}).
  3. Enter Target n to compute the nth term of the sequence.
  4. Review a(n) Value from the iterative calculation and the Closed-Form Estimate.
  5. Use the Closed-Form Estimate to identify the dominant growth rate (exponential, polynomial, etc.).

How the result changes with Target n

Target na(n) Value
1055
359,227,465
6517,167,680,177,565
902,880,067,194,370,816,000

What each input means

a₀ (initial value)
First initial condition a₀
a₁ (initial value)
Second initial condition a₁
Coefficient p
Coefficient of a_{n-1} in the recurrence a_n = p*a_{n-1} + q*a_{n-2}
Coefficient q
Coefficient of a_{n-2} in the recurrence a_n = p*a_{n-1} + q*a_{n-2}
Target n
Compute the sequence up to this index

How this is calculated

Worked example, using the default values

  1. Identify Input Parameters
    4 parameters
    a₀ (initial value) = 0, a₁ (initial value) = 1, Coefficient p = 1, Coefficient q = 1 = 5 input(s) provided
  2. Calculate a(n) Value
    a(n) Value
    55 = 55
  3. Calculate Closed-Form Estimate
    Closed-Form Estimate
    55 = 55

Engine last updated . Checked against 3 independently-derived tests how we verify calculators.

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