A113781 -id:A113781 - cp's OEIS frontend

A115921 Numbers k such that the decimal digits of phi(k) are a permutation of those of k.

1, 21, 63, 291, 502, 2518, 2817, 2991, 4435, 5229, 5367, 5637, 6102, 6174, 6543, 6822, 7236, 7422, 8022, 8541, 8982, 17631, 18231, 18261, 20301, 20518, 20617, 21058, 22471, 22851, 25196, 25918, 27615, 29817, 34816, 35683, 43218, 44305

Offset: 1

Giovanni Resta, Feb 06 2006

Contains A069215 and A113781; is itself a subsequence of A082060. - M. F. Hasler, Nov 28 2007

There is some m > 1 such that a(n) > m*n for all n > 1. This follows from the positive density of numbers n such that n/phi(n) > 10. - Charles R Greathouse IV, Sep 07 2012

			phi(20301) = 13200, phi(6543) = 4356.

V. Raman, Table of n, a(n) for n = 1..10000

Cf. A069215, A113781, A082060, A115920, A114065, A175795.

Select[Range[45000],Sort[IntegerDigits[EulerPhi[#]]]==Sort[IntegerDigits[#]]&] (* Harvey P. Dale, Jul 25 2018 *)

for(n=1,10^5,if(vecsort(Vecsmall(Str(n)))==vecsort(Vecsmall(Str(eulerphi(n)))),print1(n", "))) \\ M. F. Hasler, Nov 28 2007

from sympy import totient
A115921_list = [n for n in range(1,10**4) if sorted(str(totient(n))) == sorted(str(n))] # Chai Wah Wu, Dec 13 2015

Edited by M. F. Hasler, Nov 28 2007

A082060 Numbers n such that n and phi(n) have the same distinct decimal digits.

Original entry on oeis.org

1, 21, 63, 101, 233, 291, 502, 677, 1021, 1031, 1051, 1061, 1091, 1201, 1226, 1301, 1601, 1801, 1901, 2011, 2201, 2333, 2383, 2393, 2518, 2633, 2677, 2700, 2767, 2817, 2833, 2991, 3011, 3023, 3122, 3203, 3253, 3323, 3623, 3677, 3767, 3823, 3923, 3989

Offset: 1

Labos Elemer, Apr 04 2003

Contains A113781 as a subsequence. - M. F. Hasler, Nov 28 2007

Numbers n such that n and phi(n) have the same decimal digits = A115921. - Jaroslav Krizek, Nov 13 2014

			n=502 is a member since phi[502]=250

Harvey P. Dale, Table of n, a(n) for n = 1..2500

Cf. A000005, A000010, A082059, A115921, A113781, A113622, A069215, A072395, A113781.

Select[Range[4000],Union[IntegerDigits[#]]==Union[IntegerDigits[ EulerPhi[ #]]]&] (* Harvey P. Dale, Jan 31 2022 *)

for(n=1,10^4,if(Set(Vec(Str(n)))==Set(Vec(Str(eulerphi(n)))),print1(n", "))) \\ M. F. Hasler, Nov 28 2007

from sympy import totient
A082060_list = [n for n in range(1,10**4) if set(str(totient(n))) == set(str(n))] # Chai Wah Wu, Dec 13 2015

Definition and comment corrected by Jaroslav Krizek, Nov 13 2014

cp's OEIS Frontend

A115921 Numbers k such that the decimal digits of phi(k) are a permutation of those of k.

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