A082059 Numbers k such that k, sigma(k) and phi(k) have the same decimal digits.
1, 1021, 1201, 2011, 7687, 7867, 8677, 10211, 10271, 10321, 12011, 12041, 12071, 12101, 12301, 12343, 12401, 12433, 12601, 14323, 16787, 17021, 20011, 20101, 20161, 20411, 20611, 21001, 21011, 21031, 21061, 21101, 21401, 21433, 21601, 21701, 22343, 22433
Offset: 1
Examples
n = 89767, sigma(n) = 89768, phi(n) = 89766.
Links
- Donovan Johnson, Table of n, a(n) for n = 1..1000
Programs
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Mathematica
Select[Range[25000],Union[IntegerDigits[#]] == Union[ IntegerDigits[ DivisorSigma[ 1,#]]] == Union[IntegerDigits[EulerPhi[#]]]&] (* Harvey P. Dale, Jun 12 2014 *)
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PARI
c=0; for(n=1, 324773, m=n; nd=vector(10); for(j=1, 6, r=m%10; nd[r+1]=1; m=m\10; if(m==0, j=6)); s=sigma(n); m=s; sd=vector(10); for(j=1, 6, r=m%10; sd[r+1]=1; m=m\10; if(m==0, j=6)); for(j=1, 10, if(nd[j]<>sd[j], next(2))); p=eulerphi(n); m=p; pd=vector(10); for(j=1, 6, r=m%10; pd[r+1]=1; m=m\10; if(m==0, j=6)); for(j=1, 10, if(nd[j]<>pd[j], next(2))); c++; write("b082059.txt", c " " n)) \\ Donovan Johnson, Feb 28 2013