Duffinian numbers: Difference between revisions
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A '''Duffinian number''' is a composite number '''k'''
''The sigma sum of '''k''' is the sum of the divisors of '''k'''.''
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Duffinian numbers are very common.
It is not uncommon for two consecutive integers to be Duffinian (a Duffinian twin) (8, 9), (35, 36), (49, 50), etc.
Less common are Duffinian triplets; three consecutive Duffinian numbers. (63, 64, 65), (323, 324, 325), etc.
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