Excel BI - Excel Challenge 858

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excel-formulas

🔰 Work out the first 50 Fibonacci numbers and frequency of digits considering all 50 numbers together.

Published

March 24, 2026

Illustration for Excel BI - Excel Challenge 858

Challenge Description

🔰 Work out the first 50 Fibonacci numbers and frequency of digits considering all 50 numbers together. Find the top 3 digits on the basis of frequency of occurrence.

Solutions

library(tidyverse)
library(readxl)
library(charcuterie)

path <- "Excel/800-899/858/858 Top 3 Digits in First 50 Fibonacci Numbers.xlsx"
test <- read_excel(path, range = "A2:B5")

result <- Reduce(
  function(a, ...) c(a, sum(tail(a, 2))),
  1:48,
  init = c(0, 1)
) |>
  as.character() |>
  paste0(collapse = "") |>
  chars() |>
  table() |>
  as.data.frame() |>
  rename(Digit = 1, Frequency = 2) |>
  mutate(Digit = as.character(Digit)) |>
  slice_max(Frequency, n = 3)

all.equal(test, result, check.attributes = FALSE)

Logic: Read the workbook ranges needed for the challenge; Derive the required intermediate columns.
Strengths: The code maps the workbook rule into a compact, reproducible pipeline.
Areas for Improvement: The solution assumes the workbook layout and selected ranges remain stable, so any structural change in the sheet would require small adjustments.
Gem: The elegant part is how little code is needed once the correct intermediate representation is chosen.

import pandas as pd
import numpy as np

path = "Excel/800-899/858/858 Top 3 Digits in First 50 Fibonacci Numbers.xlsx"
test = pd.read_excel(path, usecols="A:B", skiprows=1, nrows=3)

fib = [0, 1]
for _ in range(48):
    fib.append(fib[-1] + fib[-2])
digits = "".join(str(x) for x in fib)
freq = pd.Series(list(digits)).value_counts().reset_index()
freq.columns = ["Digit", "Frequency"]
freq["Digit"] = freq["Digit"].astype('int64')
result = freq.nlargest(3, "Frequency").reset_index(drop=True)

print(test.equals(result))  # Should output: True

The Python version keeps the algorithm explicit, which helps when the challenge depends on a greedy or iterative rule.

Difficulty Level

Easy / Medium

The business rule is clear, though the workbook still needs a few transformation steps to reach the expected output.