My Math Forum  

Go Back   My Math Forum > College Math Forum > Number Theory

Number Theory Number Theory Math Forum


Reply
 
LinkBack Thread Tools Display Modes
April 18th, 2019, 12:43 AM   #1
RTn
Newbie
 
Joined: Apr 2019
From: Europe

Posts: 1
Thanks: 0

Expression for finding common elements in two series

Hello,
First of, I am sorry if I am posting it in a wrong section. If so, can someone please move this thread to the appropriate section?

Now, my problem:
I have a series of the form S1=x(x+1)
and another series S1/k, for any k∈N. Now I want to find the values where the elements of two series are equal. For example, let k be 3, then the intersection of the two series gives 2,30,420,5852,81510,1135290. Can a formula be derived to find these ways without resorting to equating the two series and deriving quadratic roots i.e. using series formulae or triangular numbers etc.?
RTn is offline  
 
April 19th, 2019, 11:58 AM   #2
Senior Member
 
Joined: Dec 2015
From: somewhere

Posts: 605
Thanks: 88

Without equating them then use divisibility rule.
$\displaystyle k|x(x+1)$ or S1 is divisible by k.
S1(mod)k=0 .To continue use modular arithmetics.
idontknow is offline  
Reply

  My Math Forum > College Math Forum > Number Theory

Tags
common, elements, expression, finding, number theory, sequence and series, series



Thread Tools
Display Modes


Similar Threads
Thread Thread Starter Forum Replies Last Post
How do I find the number of elements in a problem involving least common multiples? Chemist116 Pre-Calculus 16 February 24th, 2018 01:05 PM
Help with finding the Least Common Multiple(I think) geekchick Algebra 4 June 28th, 2017 12:15 PM
Finding the number of elements of order 2 in a given group Ganesh Ujwal Abstract Algebra 4 April 14th, 2015 10:48 AM
Finding all the elements in S_5 interestedinmaths Abstract Algebra 2 December 27th, 2012 06:47 AM
Common elements dajaka Number Theory 3 October 30th, 2008 01:25 PM





Copyright © 2019 My Math Forum. All rights reserved.