Even Fibonacci numbers

Excel BI’s Excel Challenge #316 — solved in R

Defining the Puzzle:

Probably everyone of us have heard of Fibonacci Numbers. It is a sequence that property is that next number is a sum of two previous. But this time ExcelBI asked us to generate… first 20 even elements of this sequence.

Loading data:

Today we have only data to check if our sequence is exactly the same.

library(tidyverse)
library(readxl)

test = read_excel(“Even Fibonacci Numbers.xlsx”, range = “A1:A21”) %>% pull()

Approach:

As it looks pretty easy task and giving three approaches in different frameworks will change only small chunk of code. That there will be only one code today.

generate_even_fibonacci <- function() {
 fibonacci_sequence <- c(1, 2)
 even_fibonacci <- c(0, 2) 
 
 while (length(even_fibonacci) < 20) {
 next_fibonacci <- sum(tail(fibonacci_sequence, 2))
 fibonacci_sequence <- c(fibonacci_sequence, next_fibonacci)
 if (next_fibonacci %% 2 == 0) {
 even_fibonacci <- c(even_fibonacci, next_fibonacci)
 }
 }
 
 return(even_fibonacci)
}

even_fibonacci <- generate_even_fibonacci()

Validate result:

identical(even_fibonacci, test)
# > TRUE

If you like my publications or have your own ways to solve those puzzles in R, Python or whatever tool you choose, let me know.