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.

Even Fibonacci numbers was originally published in Numbers around us on Medium, where people are continuing the conversation by highlighting and responding to this story.