Semiprime: Difference between revisions
→implement
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</pre>
=={{header|Prolog}}==
works with swi-prolog
<syntaxhighlight lang="prolog">
factors(N, FList):-
factors(N, 2, 0, FList).
factors(1, _, _Count, []).
factors(_, _, Count, []):- Count > 1. % break on 2 factors reached
factors(N, Start, Count, [Fac|FList]):-
N1 is floor(sqrt(N)),
between(Start, N1, Fac),
N mod Fac =:= 0,!,
N2 is N div Fac,
Count1 is Count + 1,
factors(N2, Fac, Count1, FList).
factors(N, _, _, [N]):- N >= 2.
semiPrimeList(Limit, List):-
findall(N, semiPrimes(2, Limit, N), List).
semiPrimes(Start, Limit, N):-
between(Start, Limit, N),
factors(N, [F1, F2]),
N =:= F1 * F2. % correct factors break
do:- semiPrimeList(100, SemiPrimes),
writeln(SemiPrimes),
findall(N, semiPrimes(1675, 1685, N), SemiPrimes2),
writeln(SemiPrimes2).
</syntaxhighlight>
{{out}}
<pre>
?- do.
[4,6,9,10,14,15,21,22,25,26,33,34,35,38,39,46,49,51,55,57,58,62,65,69,74,77,82,85,86,87,91,93,94,95]
[1678,1679,1681,1685]
true.
</pre>
=={{header|PROMAL}}==
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