Data update

Task/Totient-function/PascalABC.NET/totient-function.pas

@@ -0,0 +1,17 @@
+uses school;
+
+function totient(n: int64) := (1..n).Select(k -> (if gcd(n, k) = 1 then 1 else 0)).Sum;
+
+function is_prime(n: int64) := totient(n) = n - 1;
+
+begin
+  foreach var n in 1..25 do
+    writeln('φ(', n, ') = ', totient(n), if is_prime(n) then ', is prime' else '');
+  var count := 0;
+  foreach var n in 1..100_000 do
+  begin
+    count += if is_prime(n) then 1 else 0;
+    if n in |100, 1000, 10_000, 100_000| then
+      writeln('Primes up to ', n, ': ', count);
+  end;
+end.