Data commit

Task/Arithmetic-Rational/Prolog/arithmetic-rational.pro

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+divisor(N, Div) :-
+    Max is floor(sqrt(N)),
+    between(1, Max, D),
+    divmod(N, D, _, 0),
+    (Div = D; Div is N div D, Div =\= D).
+
+divisors(N, Divs) :-
+    setof(M, divisor(N, M), Divs).
+
+recip(A, B) :- B is 1 rdiv A.
+
+sumrecip(N, A) :-
+    divisors(N, [1 | Ds]),
+    maplist(recip, Ds, As),
+    sum_list(As, A).
+
+perfect(X) :- sumrecip(X, 1).
+
+main :-
+    Limit is 1 << 19,
+    forall(
+        (between(1, Limit, N), perfect(N)),
+	(format("~w~n", [N]))),
+    halt.
+
+?- main.