25 lines
706 B
Text
25 lines
706 B
Text
;Definition
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A '''Giuga number''' is a composite number '''n''' which is such that each of its distinct prime factors
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'''f''' divide (n/f - 1) exactly.
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All known Giuga numbers are even though it is not known for certain that there are no odd examples.
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;Example
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30 is a Giuga number because its distinct prime factors are 2, 3 and 5 and:
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* 30/2 - 1 = 14 is divisible by 2
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* 30/3 - 1 = 9 is divisible by 3
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* 30/5 - 1 = 5 is divisible by 5
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<br>
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;Task
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Determine and show here the first four Giuga numbers.
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;Stretch
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Determine the fifth Giuga number and any more you have the patience for.
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;References
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* [[wp:Giuga_number|Wikipedia: Giuga number]]
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* [[oeis:A007850|OEIS:A007850 - Giuga numbers]]
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<br><br>
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