OU-Sigma function
y.kohmoto
zbi74583 at boat.zero.ad.jp
Sat Feb 14 10:50:44 CET 2004
Hello, Seqfans
I considered an artificial divisor function as follows.
Definition of ordinary unitary sigma :
If n=Product p_i^r_i then
OU-Sigma(n)=Sigma(2^r_1)*UnitarySigma(n/2^r_1)
=(2^(r_1+1)-1)*Product(p_i^r_i+1) , p_i is not 2
e.i.
OU-Sigma(2^4*7^2)=Sigma(2^4)*UnitarySigma(7^2)=31*50=1550
So, OU-Sigma(n) = Sigma(n) if n=2^r
= UnitarySigma(n) if GCD(2,n)=1
I calculated OU-Sigma perfect number.
OU-Sigma(n) = k*n
sequence of OU-Sigma perfect number :
2*3, 2*3^2*5, 2^2*7, 2^2*5^2*7^2*13, 2^3*3*5, 2^4*31, 2^5*3^2*5*7,
2^6*127, 2^7*3^3*5*7*17*, 2^7*3^4*5*7*17*41, 2^8*5*7*19*37*73,
2^8*3*5*7*19*37*73, 2^9*3*11*31, 2^9*3^2*5*11*31, 2^10*3^3*5*7*23*89,
2^10*3^4*5*7*23*41*89, 2^11*3^3*5*7^3*11*13*43, 2^11*3^4*5*7^3*11*13*41*43,
2^12*8191,
sequence of k :
2, 2, 2, 2, 3, 2, 3, 2, 3, 3, 3, 4, 3, 3, 3, 3, 3, 3, 2,
The sequence contains perfect numbers.
Because,
OE-Sigma(2^(m-1)*M_m) = Sigma(2^(m-1))*UnitarySigma(M_m)
= Sigma(2^(m-1))*Sigma(M_m)
= 2^m*M_m
To Neil :
Do you need this sequence?
If Yes then I will format it, and if No then I will throw it in my junk
box.
Yasutoshi
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