Data update

Task/M-bius-function/Forth/m-bius-function.fth

@@ -0,0 +1,36 @@
+\ Moebius function
+: mu ( u -- n )
+  \ multiple of 4 so return 0
+  dup 3 and 0= if drop 0 exit then
+  \ even numbers have 2 as a prime factor
+  dup 1 and 0= if 2/ 1 else 0 then >r
+  \ look for odd prime factors up to the square root
+  3 begin
+    2dup dup * >=
+  while
+    2dup mod 0= if
+      tuck / swap
+      2dup mod 0= if
+        \ repeated prime factor so return 0
+        2drop rdrop 0 exit
+      then
+       \ we have another prime factor
+      r> 1+ >r
+    then
+    2 +
+  repeat
+  drop
+  \ prime factor > square root?
+  r> swap 1 > if 1+ then
+  1 and 0= if 1 else -1 then ;
+
+: main ( -- )
+  ." The first 199 Moebius numbers are:" cr
+  ."    "
+  200 1 do
+    i mu 3 .r
+    i 1+ 20 mod 0= if cr else then
+  loop ;
+
+main
+bye

Task/M-bius-function/PascalABC.NET/m-bius-function.pas

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+uses school;
+
+function mobius(n: integer): integer;
+begin
+  var factors := n.Factorize;
+  if factors.Count = factors.ToSet.Count then
+    result := if factors.Count.IsEven then 1 else -1
+  else result := 0
+end;
+
+begin
+  println('Mobius numbers from 1..99:');
+  for var n := 1 to 99 do
+    write(mobius(n):3, if n mod 20 = 0 then #10 else '');
+end.

Task/M-bius-function/Swift/m-bius-function.swift

@@ -0,0 +1,36 @@
+import Foundation
+
+// Moebius function
+func mu(number: Int) -> Int {
+    var n = number
+    if n % 4 == 0 {
+        return 0
+    }
+    var primeFactors = 0
+    if n % 2 == 0 {
+        primeFactors += 1
+        n /= 2
+    }
+    var p = 3
+    while p * p <= n {
+        if n % p == 0 {
+            n /= p
+            if n % p == 0 {
+                return 0
+            }
+            primeFactors += 1
+        }
+        p += 2
+    }
+    if (n > 1) {
+        primeFactors += 1
+    }
+    return primeFactors % 2 == 0 ? 1 : -1
+}
+
+print("The first 199 Moebius numbers are:")
+print("   ", terminator: "")
+for i in 1..<200 {
+    print(String(format: "%3d", mu(number: i)),
+            terminator: (i + 1) % 20 == 0 ? "\n" : "")
+}