[seqfan] Re: Relationship between RMPN and RAN
M. F. Hasler
oeis at hasler.fr
Thu Oct 31 12:11:13 CET 2013
Cf. A160320 (sigma(n)/n=k+1/3), A160321 (sigma(n)/n=k+2/3), A159907
(sigma(n)/n=k+1/2).
See also http://www.numericana.com/answer/numbers.htm#multiperfect
(for half-integral values)
Maximilian
On Wed, Oct 30, 2013 at 8:40 PM, <zbi74583.boat at orange.zero.jp> wrote:
> Hi, Seqfans
>
> [ Relationship between Rational Multiply Perfect Number and Rational
> Amicable Number ]
>
> [ Definition ]
>
> RMPN :
> Sigma(m)=k*m , where k is Rational Number
>
> RAN :
> Sigma(m)=Sigma(n)=F(m,n) , where F(m,n) is Rational formula of m,n
>
> http://mathworld.wolfram.com/RationalAmicablePair.html
>
> [ How to solve ]
>
> Example ;
>
> Sigma(x)=Sigma(y)=(x+y)^3/(x^2+y^2) ....E0
>
> Let
> x=c*n
> y=c*m
> GCD(c,n)=1 , GCD(c.m)=1
>
> From E0
> Sigma(c*n)=Sigma(c*m)
> Hence
> Sigma(n)=Sigma(m) - E1 -
>
> From E0
> Sigma(c*n)=c*(n+m)^3/(n^2+m^2)
> Hence
> Sigma(c)=k*c , k=(n+m)^3/((n^2+m^2)*Sigma(n)) - E2 -
> c is RMPN
>
> If we try with
> n=33 , m=47
>
> It satisfies E1 , because
> Sigma(3*11)=48
> Sigma(47)=48
>
> k=80^3/(2*17*97*3*2^4)
> =2^7*6^3/2*17*97
>
> We compute c
> c=2^2*3^3*7^3*17*97
>
> Unfortunatly
> GCD(c,n)=3 is not 1
> So, (c*n, c*m) is not RAN
>
>
> If we try with (n,m) which is not smooth and n+m is smooth then (c*n, c*m)
> becomes RAN
> Where n is smooth means all prime factors of n are small
> Where m is small means m<100
>
> To compute RMPN is neccesary for solving RAN.
> So, RMPN is important and interesting problem.
>
> I am going to compute all RMPN such that k=n/m<7 and m<100.
> I computed these RMPN in my hand, exactly in my mind.
>
> Could anyone confirm them and compute their decimal expression?
> If you found the other solution, then tell me it.
>
> [ RMPN k=m/3 4<=m<=19 ]
>
> 4/3
> 3
>
> 7/3
> 2^2*3
> 2*3^2*13
>
> 8/3
> 3*2^(m-1)*M_m
> Where M_m means Mersenne prime 2^m-1
> 2*3^2*7*13
> 2*3^3*5
>
> 10/3
> 2^3*3^2*7*13
> 2^3*3^3*5
> 2^7*3^6*17*23*137*547*1093
> 2^25*3^6*19*23*137*547*683*1093*2731*8191
> 2^13*3^3*11*43*127
>
> 11/3
> 2^3*3^4*5*11
> 2^5*3^4*7*11
> 2^9*3^2*7*13*31
> 2^9*3^3*5*31
> 2^13*3^2*7*13*43*127
> 2^13*3^3*5*43*127
>
> 13/3
> 2^8*3^2*5*7*19*37*73
> 2^14*3^2*5*7*19*31*151
> 2^11*3^3*5^2*7*31
> 2^11*3^6*5*7*23*137*547*1093
> 2^7*3^5*5*7*17
> 2^10*3^5*5*7*23*89
> 2^25*3^5*5*7*19*2731*8191
>
> 14/3
> 2^5*3^4*5*7*11^2*19
> 2^7*3^4*5^2*11^2*17*19*31
> 2^10*3^4*5^2*11^2*23*19*31*89
> 2^11*3^3*5^2*7*13*31
> 2^8*3^2*5*7*13*19*37*73
> 2^14*3^2*5*7*13*19*31*151
> 2^7*3^7*5^2*11*17*31*41*43
> 2^17*3^7*5*7*19^2*37*41*73*127
> 2^11*3^6*5*7*13*23*137*547*1093
> 2^5*3^5*5*7^2*13*19
> 2^7*3^5*5*7*13*17
> 2^10*3^5*5*7*13*23*89
> 2^11*3^5*5*7*13^2*31*61
> 2^25*3^5*5*7*13*19*2731*8191
>
> 16/3
> 2^15*3^7*5^2*7*11*17*31*41*43*257
> 2^7*3^4*5^2*7*11^2*17*19*31
> 2^7*3^5*5^2*7^2*13*17*19*31
> 2^10*3^4*5^2*7*11^2*19*23*31*89
> 2^10*3^5*5^2*7^2*13*19*23*31*89
> 2^13*3^5*5*7^2*11*13*19*43*127
>
> 17/3
> 2^15*3^5*5^2*7^2*11*13*19*31*43*257
>
> 19/3
> 2^24*3^8*5^2*7*11*13^2*17*19*31^3*37*43*53*61*379*601*757*1801
> Only this one I used my note book computer.
>
> Neil you may find many sequences in this result.
>
>
>
> Yasutoshi
>
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>
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