A062955 a(n) = phi(n^2) - phi(n) = (n-1) * phi(n).

0, 1, 4, 6, 16, 10, 36, 28, 48, 36, 100, 44, 144, 78, 112, 120, 256, 102, 324, 152, 240, 210, 484, 184, 480, 300, 468, 324, 784, 232, 900, 496, 640, 528, 816, 420, 1296, 666, 912, 624, 1600, 492, 1764, 860, 1056, 990, 2116, 752, 2016, 980, 1600, 1224, 2704

Offset: 1

Author

Jason Earls, Jul 22 2001

Keywords

• nonn

Links

• Harry J. Smith, Table of n, a(n) for n = 1..1000

Crossrefs

Cf. A000010, A002618.

Programs

Mathematica

Table[EulerPhi[n^2]-EulerPhi[n],{n,60}] (* Harvey P. Dale, Aug 22 2012 *)

PARI

a(n)=if(n<1,0,eulerphi(n^2)-eulerphi(n))

PARI

{ for (n=1, 1000, write("b062955.txt", n, " ", eulerphi(n^2) - eulerphi(n)) ) } \\ Harry J. Smith, Aug 14 2009

Formula

a(n) = A002618(n) - A000010(n). - Michel Marcus, Jun 28 2018