Initial data commit

Task/Amicable-pairs/AppleScript/amicable-pairs-3.applescript

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+on properDivisors(n)
+    set output to {}
+
+    if (n > 1) then
+        set sqrt to n ^ 0.5
+        set limit to sqrt div 1
+        if (limit = sqrt) then
+            set end of output to limit
+            set limit to limit - 1
+        end if
+        repeat with i from limit to 2 by -1
+            if (n mod i is 0) then
+                set beginning of output to i
+                set end of output to n div i
+            end if
+        end repeat
+        set beginning of output to 1
+    end if
+
+    return output
+end properDivisors
+
+on sumList(listOfNumbers)
+    script o
+        property l : listOfNumbers
+    end script
+    set sum to 0
+    repeat with n in o's l
+        set sum to sum + n
+    end repeat
+
+    return sum
+end sumList
+
+on amicablePairsBelow(limitPlus1)
+    script o
+        property pdSums : {missing value} -- Sums of proper divisors. (Dummy item for 1's.)
+    end script
+    set limit to limitPlus1 - 1
+    repeat with n from 2 to limit
+        set end of o's pdSums to sumList(properDivisors(n))
+    end repeat
+
+    set output to {}
+    repeat with n1 from 2 to (limit - 1)
+        set n2 to o's pdSums's item n1
+        if ((n1 < n2) and (n2 < limitPlus1) and (o's pdSums's item n2 = n1)) then ¬
+            set end of output to {n1, n2}
+    end repeat
+
+    return output
+end amicablePairsBelow
+
+on join(lst, delim)
+    set astid to AppleScript's text item delimiters
+    set AppleScript's text item delimiters to delim
+    set txt to lst as text
+    set AppleScript's text item delimiters to astid
+    return txt
+end join
+
+on task()
+    set output to amicablePairsBelow(20000)
+    repeat with thisPair in output
+        set thisPair's contents to join(thisPair, " & ")
+    end repeat
+    return join(output, linefeed)
+end task
+
+task()