A255219 Squarefree numbers k such that mu(k) = mu(phi(k)) where mu(k) is the Möbius function and phi(k) is Euler's totient function.
1, 3, 14, 22, 31, 43, 46, 67, 71, 79, 94, 103, 118, 131, 139, 166, 191, 214, 223, 239, 283, 311, 334, 358, 367, 419, 422, 431, 439, 443, 454, 499, 526, 599, 607, 619, 643, 647, 659, 662, 683, 694, 718, 743, 766, 787, 823, 827, 907, 926, 934, 947, 958, 971, 1006
Offset: 1
Keywords
Examples
31 is a term since mu(31) = -1 and mu(phi(31)) = mu(30) = -1. 7 is not a term since mu(7) = -1 and mu(phi(7)) = mu(6) = 1. 24 is not a term since mu(24) = 0 (i.e., 24 is not squarefree).
Links
- Amiram Eldar, Table of n, a(n) for n = 1..10000
Programs
-
Mathematica
Select[Range[1000], Abs[MoebiusMu[#] + MoebiusMu[EulerPhi[#]]] == 2 &] (* Alonso del Arte, Feb 17 2015 *)
-
PARI
for(n=1, 1006, if(abs(moebius(n) + moebius(eulerphi(n))) == 2, print1(n,", "))) \\ Indranil Ghosh, Mar 10 2017
-
Sage
[n for n in [1..1006] if moebius(n)==moebius(euler_phi(n)) if moebius(n)!=0]
Comments