Good Afternoon (Woof in dogspeak), to my dog and cat readers,
Recently during my long stays in the kennel of boredom, I have been reading up on Friendly numbers, not to be confused with Amicable numbers. Even numbers need friends! Simply put, a number is a friend to another if the fraction of the sum of its divisors over itself is equal to the fraction of another number.
Example time!
6 and 28 are friendly. Very friendly in fact, they visit for tea every wednesday.
Divisors of 6: 1+2+3+6 total: 12
Divisors of 28: 1+2+4+7+14+28 total: 56
Fraction of 6: 12/6 = 2
Fraction of 28: 56/28 = 2
The fractions are the same, therefore the numbers are friendly. Hooray!
PS: can you find any numbers wanting to be friends?
1 comment:
You've lost me already with the "fraction of the sum of its divisors." Maybe if I took the time to work out the math.... but who has that kind of time? I do agree, numbers need to be more than amicable, they need to be friends. Preferably, friendly to me when I need them to behave in times of dire need.
I'm laughing. So glad 6 and 28 have tea every Wednesday.
The example helps. A lot.
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