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Determine-number-s-that-is-are-comprised-of-four-distinct-prime-factors-such-that-difference-of-largest-and-smallest-prime-factors-is-equal-to-the-sum-of-remaining-two-factors-Prop




Question Number 9025 by Rasheed Soomro last updated on 15/Nov/16
Determine number/s that is/are comprised  of four distinct prime factors such that  difference of largest and smallest prime  factors is equal to the sum of remaining  two factors.                  _(Propsed by Rasheed Soomro)
Determinenumber/sthatis/arecomprisedoffourdistinctprimefactorssuchthatdifferenceoflargestandsmallestprimefactorsisequaltothesumofremainingtwofactors.PropsedbyRasheedSoomro
Commented by FilupSmith last updated on 15/Nov/16
Do you mean:  n=p_1 p_2 p_3 p_4   p_a >p_(a+1)   p_1 −p_4 =p_2 +p_3   p_a ∈P, p_a ≠p_(a+i) ∀i/{0}  n=?
Doyoumean:n=p1p2p3p4pa>pa+1p1p4=p2+p3paP,papa+ii/{0}n=?
Commented by Rasheed Soomro last updated on 16/Nov/16
Yes Filup I mean that.
YesFilupImeanthat.
Commented by FilupSmith last updated on 16/Nov/16
working/playing around  x=p_1 p_2 p_3 p_4      p_1 −p_4 =p_2 +p_3   p_1 =p_2 +p_3 +p_4   ∴ x=(p_2 +p_3 +p_4 )p_2 p_3 p_4   ∴p_2 +p_3 +p_4 ∈P    p_2 +p_3 +p_4 <p_2 <p_3 <p_4   p_2 <p_2 −p_3 <−p_4 <−p_3      p_2  is +ve  p_2 −p_3  is −ve  −p_4   and  −p_3    are −ve     ∴i dont think such number exists  as the equality is not possible  working/playing around
working/playingaroundx=p1p2p3p4p1p4=p2+p3p1=p2+p3+p4x=(p2+p3+p4)p2p3p4p2+p3+p4Pp2+p3+p4<p2<p3<p4p2<p2p3<p4<p3p2is+vep2p3isvep4andp3areveidontthinksuchnumberexistsastheequalityisnotpossibleworking/playingaround
Commented by mrW last updated on 16/Nov/16
when I take a look at the table of   prime numbers I think there  should be infinitely many such  numbers, such as  x=3×5×11×19  x=5×7×11×23  x=3×7×13×23  etc.
whenItakealookatthetableofprimenumbersIthinkthereshouldbeinfinitelymanysuchnumbers,suchasx=3×5×11×19x=5×7×11×23x=3×7×13×23etc.
Commented by Rasheed Soomro last updated on 16/Nov/16
^• THαnks of you both!  ^• Good attack of Filup  to the problem but  failed in the end!  ^• I also think that such numbers are infinite  but  Can we prove that such numbers are infimite?
THαnksofyouboth!GoodattackofFiluptotheproblembutfailedintheend!IalsothinkthatsuchnumbersareinfinitebutCanweprovethatsuchnumbersareinfimite?
Commented by FilupSmith last updated on 16/Nov/16
I wonder where I went wrong
IwonderwhereIwentwrong
Commented by FilupSmith last updated on 16/Nov/16
I think my mistake was that in my math,  p_1  is actually >p_2 , but i missthought  it as p_1 <p_2 , or vica versa.     Everything up to  x=(p_2 +p_3 +p_4 )p_2 p_3 p_4   is correct. BUT,  it should be that:  p_1 >p_2 >p_3 >p_3 .
Ithinkmymistakewasthatinmymath,p1isactually>p2,butimissthoughtitasp1<p2,orvicaversa.Everythinguptox=(p2+p3+p4)p2p3p4iscorrect.BUT,itshouldbethat:p1>p2>p3>p3.

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