Initial data commit

Task/M-bius-function/Jq/m-bius-function-4.jq

@@ -0,0 +1,21 @@
+def isSquareFree:
+  . as $n
+  | 2
+  | until ( (. * . > $n) or . == 0;
+       if ($n % (.*.) == 0) then 0 # i.e. stop
+       elif . > 2 then . + 2
+       else . + 1
+       end  )
+  | . != 0;
+
+def mu:
+  . as $n
+  | if . < 1 then "Argument to mu must be a positive integer" | error
+    elif . == 1 then 1
+    else if isSquareFree
+         then if ((prime_factors|length) % 2 == 0) then 1
+              else -1
+              end
+         else 0
+         end
+    end;