Rosetta Code

Fibonacci n-step number sequences

Generate Tribonacci and Tetranacci sequences by summing the previous n terms.

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Sourcerosettacode/popular/fibonacci_n_step_number_sequences.vibe
def trailing_sum(values: array<int>, count: int) -> int
  total = 0
  index = values.length - count

  while index < values.length
    total = total + values.fetch(index)
    index = index + 1
  end

  total
end

def n_step_sequence(seed: array<int>, count: int) -> array<int>
  values: array<int> = []
  index = 0

  while index < seed.length && values.length < count
    values.push(seed.fetch(index))
    index = index + 1
  end

  while values.length < count
    values.push(trailing_sum(values, seed.length))
  end

  values
end

def run -> { tetranacci: array<int>, tribonacci: array<int> }
  {
    tribonacci: n_step_sequence([0, 0, 1], 12),
    tetranacci: n_step_sequence([0, 0, 0, 1], 12)
  }
end

Output

Click Run example to see the result.

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