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912
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location Madrid, Spain
age 51
visits member for 4 years, 1 month
seen 3 hours ago

Nov
1
comment Half the rationals?
I think there something missing in the right hand side of the inequality $\sum_{k=1}^{n-1} a_k\phi(k) < 1/2$, I suppose you mean $<\frac{1}{2}\sum_{k=1}^{n-1} \phi(k)$? On the other hand, even if it is probably true, I can't see how to prove that this construction works for all the intervals $Y$.
Nov
1
comment Half the rationals?
I think that the proportion of fractions with even numerator and denominator bounded by $N$ is aproximately one third, and the same for even denominator.
Oct
15
revised Tiling a minimal perimeter region with $n$ unit squares
Sketch of proof
Oct
15
answered Tiling a minimal perimeter region with $n$ unit squares
Jul
19
answered Solving a polynomial modulo an integer
Jun
8
awarded  Caucus
Apr
19
revised Burgess on quadratic residues and non-residues
edited body
Apr
19
comment Burgess on quadratic residues and non-residues
No that's an error I correct it
Apr
19
comment Burgess on quadratic residues and non-residues
I have edited the answer to make it more clear. I hope this helps.
Apr
19
revised Burgess on quadratic residues and non-residues
added 1406 characters in body
Apr
17
revised Burgess on quadratic residues and non-residues
correction
Apr
17
answered Burgess on quadratic residues and non-residues
Feb
21
revised Is it a bad idea to use a Sieve of Eratosthenes to find all primes up to very large N?
added 1962 characters in body
Feb
21
revised Is it a bad idea to use a Sieve of Eratosthenes to find all primes up to very large N?
added 1962 characters in body
Feb
21
answered Is it a bad idea to use a Sieve of Eratosthenes to find all primes up to very large N?
Dec
20
comment Consequence of Bertrand's Postulate
It proves that for every $N$ there exist a $k$ such that there are $N$ (or more) pairs of consecutive primes with common difference $k$. The problem if there are $N$ consecutive primes with common difference $k$ is AFAIK open, though is related to Green-Tao theorem.
Dec
19
comment Consequence of Bertrand's Postulate
user19012: It was my fault there was a flaw in the argument. I have corrected it.
Dec
19
revised Consequence of Bertrand's Postulate
Correction of an error in the argument
Dec
15
revised Consequence of Bertrand's Postulate
Clarification of the argument.
Dec
15
answered Consequence of Bertrand's Postulate