Data update

Task/Goldbachs-comet/PascalABC.NET/goldbachs-comet.pas

@@ -0,0 +1,36 @@
+uses GraphWPF;
+
+const colpick = (Colors.Red, Colors.Green, Colors.Blue);
+
+function IsPrime(x: longword): boolean;
+begin
+  var i := 2;
+  while (i * i <= x) and (x mod i <> 0) do
+    i += 1;
+  Result := i * i > x;
+end;
+
+function g(n: integer): integer;
+begin
+  assert((n > 2) and (n mod 2 = 0), '“n” must be even and greater than 2.');
+  for var i := 2 to (n div 2)  do
+    if isPrime(i) and isPrime(n - i) then
+      result += 1;
+end;
+
+begin
+  println('First 100 G numbers:');
+  foreach var n in (2..101) index i do
+  begin
+    write(g( 2 * n):3);
+    if (i + 1) mod 10 = 0 then writeln;
+  end;
+  println;
+  println('G(1_000_000) =', g(1_000_000));
+
+  setMathematicCoords(0, 4000, 0, false);
+  foreach var x in range(4, 4002, 2) do
+  begin
+    fillcircle(x, g(x)*15, 10, colpick[(x div 2) mod 3]);
+  end;
+end.