Esteban Crespi
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 Dec20 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. Dec19 comment Consequence of Bertrand's Postulate user19012: It was my fault there was a flaw in the argument. I have corrected it. Dec19 revised Consequence of Bertrand's Postulate Correction of an error in the argument Dec15 revised Consequence of Bertrand's Postulate Clarification of the argument. Dec15 answered Consequence of Bertrand's Postulate Nov8 awarded Yearling Oct13 answered Solving for $x$ in $x^k \equiv b \pmod n$ where $n$ is not prime and $\gcd(k, \phi(n)) > 1$ Oct12 answered Algorithm for keeping a concrete version of Euclid's argument simple Sep26 comment How many ways can I make six moves on a Rubik's cube? @Henry: You are right. actually the number I gave allows 18 legal moves while the OP ask for 12 (90 deg twists) so the number of different positions after at most 6 moves is a lot smaller: 1056772. Actually the method given by him (make six random moves until the puzzle is solved) fails for the 96696 positions after 5 moves if it does not take this into account. Sep24 comment The number of ones in a binary representation of an integer @Matt: Why 16x increase? I'm not sure I agree, as you are substituing a few cheap operations with table lookup which needs slow memory access and messes the cache. Sep24 answered The number of ones in a binary representation of an integer Sep12 comment Bound for divisor function $\mathrm{Li} x$ is the logarithmic integral $=\int_2^x \frac{ dt}{\log t}$ see here. Sep12 answered Bound for divisor function Jun21 answered Calculating monodromy Jun20 revised Finding the integer $\le n$ with largest number of divisors added 11 characters in body Jun19 awarded Student Jun19 asked Finding the integer $\le n$ with largest number of divisors May5 comment Example of a rational function such that : $(f(x))^{3} + (g(x))^{3} + (h(x))^{3}=x$ @lhf: In the page linked by Gerry you have several solutions and links as: $(m^3-3^6n^9)^3 + (-m^3+3^5mn^6+3^6n^9)^3 + (3^3m^2n^3+3^5mn^6)^3$ $= m(3^2m^2n^2 +3^4mn^5+3^6n^8)^3$. Mar19 answered Common terms in general Fibonacci sequences Mar13 revised The number of symmetric polynomials of n degree Error Corrected