Perfect numbers: Difference between revisions
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m (→cheating: removed unused var) |
m (→{{header|Wren}}: Minor tidy) |
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{{trans|D}} |
{{trans|D}} |
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Restricted to the first four perfect numbers as the fifth one is very slow to emerge. |
Restricted to the first four perfect numbers as the fifth one is very slow to emerge. |
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<syntaxhighlight lang=" |
<syntaxhighlight lang="wren">var isPerfect = Fn.new { |n| |
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if (n <= 2) return false |
if (n <= 2) return false |
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var tot = 1 |
var tot = 1 |
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{{libheader|Wren-math}} |
{{libheader|Wren-math}} |
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This makes use of the fact that all known perfect numbers are of the form <big> (2<sup>''n''</sup> - 1) × 2<sup>''n'' - 1</sup></big> where <big> (2<sup>''n''</sup> - 1)</big> is prime and finds the first seven perfect numbers instantly. The numbers are too big after that to be represented accurately by Wren. |
This makes use of the fact that all known perfect numbers are of the form <big> (2<sup>''n''</sup> - 1) × 2<sup>''n'' - 1</sup></big> where <big> (2<sup>''n''</sup> - 1)</big> is prime and finds the first seven perfect numbers instantly. The numbers are too big after that to be represented accurately by Wren. |
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<syntaxhighlight lang=" |
<syntaxhighlight lang="wren">import "./math" for Int |
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var isPerfect = Fn.new { |n| |
var isPerfect = Fn.new { |n| |
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