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1 vote
2 answers
226 views

If a prime and its square both divide a number n, prove that $n=a^2 b^3$

Lets call a number $n$ a fortified number if $n>0$ and for every prime number $p$, if $p|n$ then $p^2|n$. Given a fortified number, prove that there exists $a,b$ such that $n=a^2b^3$. I know that ...
lemons25's user avatar
6 votes
2 answers
558 views

What is sum of totatives of n(natural numbers $ \lt n$ coprime to $n$ )?

Same question as in title: What is sum of natural numbers that are coprime to $n$ and are $ \lt n$ ? I know how to count number of them using Euler's function, but how to calculate sum?
Damaon's user avatar
  • 287
0 votes
2 answers
94 views

Prime Factorizations that divide each other

Let n have prime factorization n = p^s1 · p^s2 · · · p^sk and let m have prime factorization m = q^t1 · q^t2 · · · q^tl If n|m, what must be true about the corresponding lists of primes and the ...
sanic's user avatar
  • 447