Talk:Perfect numbers: Difference between revisions
Haskell example seems to be showing a false result
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::: The ''factors that are less than 6 are'' ... --- Another term for that is ''proper divisors''. Proper divisors of '''X''' are all (positive integer) divisors of '''X''' except '''X'''. Unity is treated as a special case. -- [[User:Gerard Schildberger|Gerard Schildberger]] 21:32, 23 March 2012 (UTC)
=Haskell example may need some attention=
Perhaps the Haskell example needs a little attention ?
It shows a list of results in which 8128 ( a perfectly perfect number ) is mysteriously followed by 8129, which looks like an accident …
(if for example, we define divisors as:
> divisors x = [d | d <- [1..x-1], x `mod` d == 0]
and perfect as
> perfect n = (n == sum (divisors n))
then
> perfect 8128
evaluates to True, but
>perfect 8129
is False ( sum (divisors 8129) == 751 )
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