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

1,2

Links

Donovan Johnson, Table of n, a(n) for n = 1..1000

Example

n = 89767, sigma(n) = 89768, phi(n) = 89766.

Mathematica

Select[Range[25000], Union[IntegerDigits[#]] == Union[ IntegerDigits[ DivisorSigma[ 1, #]]] == Union[IntegerDigits[EulerPhi[#]]]&] (* Harvey P. Dale, Jun 12 2014 *)

Prog

(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

Crossrefs

Cf. A000203 (sigma), A000010 (phi).

Sequence in context: A209620 A179032 A179033 * A081633 A020388 A362361

Adjacent sequences: A082056 A082057 A082058 * A082060 A082061 A082062

Keyword

nonn,base

Author

Labos Elemer, Apr 04 2003

Status

approved