User pranay - MathOverflow most recent 30 from http://mathoverflow.net 2013-05-25T16:17:48Z http://mathoverflow.net/feeds/user/12922 http://www.creativecommons.org/licenses/by-nc/2.5/rdf http://mathoverflow.net/questions/109509/the-inverse-of-the-euler-totient-function The Inverse of the Euler Totient Function pranay 2012-10-13T03:18:05Z 2012-10-13T06:13:34Z <p>How can we calculate the cardinality of the inverse of Totient function of any positive integer n ? I tried going through this <a href="http://www.google.co.in/url?sa=t&amp;rct=j&amp;q=inverse%2520of%2520euler%2520totient%2520gupta&amp;source=web&amp;cd=1&amp;cad=rja&amp;ved=0CCMQFjAA&amp;url=http%253A%252F%252Fwww.new.dli.ernet.in%252Frawdataupload%252Fupload%252Finsa%252FINSA_2%252F20005a81_22.pdf&amp;ei=ptx4UKLpO4_OrQf934CoDA&amp;usg=AFQjCNEKBequrFgs77Sy4fMaSdv26NmCRA&amp;sig2=w8i0QuwLcMU54WKnYyoeWA" rel="nofollow">paper</a>, but I couldn't understand the procedure.</p> <p>Thanks</p> http://mathoverflow.net/questions/59404/calculating-modular-exponentiation-if-the-exponent-is-in-base-3 calculating modular exponentiation if the exponent is in base 3 pranay 2011-03-24T08:35:39Z 2011-03-24T12:44:50Z <p>Hi , i am trying to solve such a problem as follows: say the base is 2(base 10) and exponent is 10(base 3) modulus is 10(base 10), then </p> <p>there was a bug . Thanks .</p> http://mathoverflow.net/questions/58702/number-of-divisors-of-an-integer-of-form-4n1-and-4n3 Number of divisors of an integer of form 4n+1 and 4n+3 pranay 2011-03-17T01:10:53Z 2011-03-18T16:29:32Z <p>Suppose $n$ is a large odd integer. Let $D_1(n)$ be the number of divisors of $n$ of the form $4k+1$ and let $D_3(n)$ be the number of divisors of the form $4k+3$. I would like to compute $(D_1(n),D_3(n))$. </p> <p>As Joe Silverman points out, the number of representations of $n$ as a sum of two squares of integers is $4(D_1(n)-D_3(n))$. For example, $D_1(225)=6$ and $D_3(225)=3$, so there are $4(6-3)=12$ lattice points on the circle of radius $\sqrt {225}$ centered at the origin including $(0,15)$ and $(-9,-12)$.</p> <blockquote> <p>Is there a faster way to find $(D_1(n),D_3(n))$ than factoring $n$?</p> </blockquote> <hr> <p>Original:</p> <p>Hi, one way to do so is to list all the divisors of the integer and check each if it is of the form 4n+1 or 4n+3. Is there any faster method to it, especially for large n?</p> http://mathoverflow.net/questions/55179/partitioning-a-number-into-two-sets-based-on-sum-of-digits partitioning a number into two sets based on sum of digits pranay 2011-02-12T03:27:07Z 2011-02-13T18:05:18Z <p>hi, how can one determine whether a number belongs to such a set of numbers whose every element can be divided into two sets such that the sum of digits of each set of the number is same. E.g 23450 does belong to such a set , as it can be split into two sets : (3,4,0) and (2,5) such that sum of digits in each set is the same(7). Similary 91125 belongs to such a set: (9) and (1,1,2,5). but 567 , or 34523 do not belong to such a set of numbers .</p> <p>Thanks.</p> http://mathoverflow.net/questions/109509/the-inverse-of-the-euler-totient-function/109511#109511 Comment by pranay pranay 2012-10-13T08:04:10Z 2012-10-13T08:04:10Z thanks Eric, but for calculations what's o(1) ? http://mathoverflow.net/questions/99773/finding-the-value-of-x-for-an-equation Comment by pranay pranay 2012-06-16T10:14:51Z 2012-06-16T10:14:51Z thanks Chandrasekhar for the guidance http://mathoverflow.net/questions/59736/generating-a-series Comment by pranay pranay 2011-03-27T17:02:52Z 2011-03-27T17:02:52Z This is a sequence i need as a part of a question where i need to calculate the nth term. so in that case if 18th term is asked, then 18 in base 10 = 102 in base 4 = 325 after mapping = 61 in base 10 but answer is 73 http://mathoverflow.net/questions/59736/generating-a-series Comment by pranay pranay 2011-03-27T16:27:40Z 2011-03-27T16:27:40Z any C programme? http://mathoverflow.net/questions/59404/calculating-modular-exponentiation-if-the-exponent-is-in-base-3 Comment by pranay pranay 2011-03-24T09:05:47Z 2011-03-24T09:05:47Z sorry, corrected. http://mathoverflow.net/questions/58702/number-of-divisors-of-an-integer-of-form-4n1-and-4n3/58795#58795 Comment by pranay pranay 2011-03-22T11:56:03Z 2011-03-22T11:56:03Z Thanks a lot :) , i too found the same solution in one of the books . http://mathoverflow.net/questions/58702/number-of-divisors-of-an-integer-of-form-4n1-and-4n3/58709#58709 Comment by pranay pranay 2011-03-17T02:02:55Z 2011-03-17T02:02:55Z Thanks, but i was thinking if there exists any method not involving factorisation.. http://mathoverflow.net/questions/55179/partitioning-a-number-into-two-sets-based-on-sum-of-digits Comment by pranay pranay 2011-02-12T17:53:01Z 2011-02-12T17:53:01Z By simple brute-force method it would take long time to find such numbers among a range. So is there any better solution to it? Maybe by using bit operations?