Amicable pairs: Difference between revisions

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 $constant search_limit = 20000
+var a, b, count = integer
-rem - return p mod q
+dim integer sumf(search_limit)
-function mod(p, q = integer) = integer
-end = p - q * (p / q)
+print "Searching up to"; search_limit; " for amicable pairs:"
-rem - return sum of the proper divisors of n
-function sumf(n = integer) = integer
+rem - set up the table of proper divisor sums
-var f1, f2, sum = integer
-sum = 1
+for a = 1 to search_limit
-f1 = 2
-while (f1 * f1) <= n do
+   sumf(a) = 1
+next a
-  begin
-    if mod(n, f1) = 0 then
+for a = 2 to search_limit
+   b = a + a
+   while (b > 0) and (b <= search_limit) do
       begin
-        sum = sum + f1
+         sumf(b) = sumf(b) + a
-        f2 = n / f1
+         b = b + a
-        if f2 > f1 then sum = sum + f2
       end
+next a
-    f1 = f1 + 1
-  end
+rem - search for pairs using the table
-end = sum
-rem - main program begins here
-var a, b, count = integer
-print "Searching up to"; search_limit; " for amicable pairs:"
 count = 0
-for a = 2 to search_limit do
+for a = 2 to search_limit
    b = sumf(a)
-   if b > a then
+   if (b > a) and (b < search_limit) then
       if a = sumf(b) then
         begin
@@ Line 6,070: / Line 6,068: @@
 end
-</syntaxhighlight>
 {{out}}
 <pre>