Data commit

Task/Totient-function/Ruby/totient-function.rb

@@ -0,0 +1,14 @@
+require "prime"
+
+def 𝜑(n)
+  n.prime_division.inject(1) {|res, (pr, exp)| res *= (pr-1) * pr**(exp-1) }
+end
+
+1.upto 25 do |n|
+  tot = 𝜑(n)
+  puts "#{n}\t #{tot}\t #{"prime" if n-tot==1}"
+end
+
+[100, 1_000, 10_000, 100_000].each do |u|
+  puts "Number of primes up to #{u}: #{(1..u).count{|n| n-𝜑(n) == 1} }"
+end