A073464 - OEIS

%I #20 May 26 2026 03:56:29

%S 0,0,0,1,2,2,0,2,0,0,4,0,0,2,2,2,6,2,0,4,2,4,8,2,3,0,3,8,8,8,5,9,5,2,

%T 1,0,6,0,4,1,12,0,6,10,8,1,1,12,5,2,9,4,2,8,8,4,12,7,16,6,12,0,14,12,

%U 2,9,13,6,5,10,4,9,15,19,15,18,3,12,10,10,18,13,1,18,19,10,17,16,0,0,20,12

%N a(n) = phi(n) mod PrimePi(n).

%H Vincenzo Librandi, <a href="/A073464/b073464.txt">Table of n, a(n) for n = 2..10000</a>

%F a(n) = A000010(n) mod A000720(n).

%t Table[Mod[EulerPhi[w], PrimePi[w]], {w, 2, 100}]

%o (PARI) a(n) = eulerphi(n) % primepi(n); \\ _Michel Marcus_, Dec 11 2018

%o (Magma) [EulerPhi(n) mod #PrimesUpTo(n): n in [2..100]]; // _Vincenzo Librandi_, Dec 11 2018

%Y Cf. A000010, A000720.

%Y Cf. A037228, A037171.

%Y Cf. A073453, A073454, A073455, A073456, A073457, A072530, A072531, A073461, A073461.

%K nonn

%O 2,5

%A _Labos Elemer_, Aug 02 2002