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That there is currently 666 messages in the inbox
Edit - perhaps 6 unfairly gets a bad rap..
In number theory, a perfect number is a positive integer that is equal to the sum of its proper positive divisors, that is, the sum of its positive divisors excluding the number itself (also known as its aliquot sum). Equivalently, a perfect number is a number that is half the sum of all of its positive divisors (including itself) i.e. ?1(n) = 2n.
The first perfect number is 6, because 1, 2, and 3 are its proper positive divisors, and 1 + 2 + 3 = 6. Equivalently, the number 6 is equal to half the sum of all its positive divisors: ( 1 + 2 + 3 + 6 ) / 2 = 6.
The next perfect number is 28 = 1 + 2 + 4 + 7 + 14. This is followed by the perfect numbers 496 and 8128 (sequence OEIS?A000396).
These first four perfect numbers were the only ones known to early Greek mathematics, and the mathematician Nicomachus had noted 8,128 as early as 100 AD.[1]
Then, in 1456, an unknown mathematician recorded the earliest reference to a fifth perfect number, with 33,550,336 being correctly identified for the first time.[2]
In 1588, the Italian mathematician Pietro Cataldi identified the sixth perfect number (8,589,869,056)[3] and the seventh (137,438,691,328).[4]
Edited 1 time(s). Last edit at 10/19/2011 03:30AM by flamenwerfer.
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