A329204 Number of integers less than n having at least as many totatives as n.

0, 1, 0, 1, 0, 3, 0, 2, 1, 4, 0, 6, 0, 4, 2, 3, 0, 8, 0, 6, 3, 5, 0, 10, 1, 6, 3, 8, 0, 16, 0, 7, 4, 9, 2, 15, 0, 9, 4, 14, 0, 21, 0, 10, 7, 9, 0, 21, 2, 15, 5, 11, 0, 22, 5, 14, 7, 11, 0, 33, 0, 12, 10, 12, 3, 29, 0, 15, 6, 26, 0, 28, 0, 16, 13, 18, 4, 34, 0, 24, 7, 17

Offset: 1

Author

Joshua Oliver, Nov 22 2019

Keywords

• nonn
• look

Examples

			a(6) = 3, because 6 has 2 totatives and there are 3 integers less than 6 with 2 or more totatives: 3 with 2 totatives, 4 with 2 totatives, and 5 with 4 totatives.
		

Links

• Charles R Greathouse IV, Table of n, a(n) for n = 1..10000 (first 2000 terms from Joshua Oliver)
• Wikipedia, Totative.

Crossrefs

Cf. A000010.

Programs

Mathematica

Table[Length[Select[Range[n-1],EulerPhi[#]>=EulerPhi[n]&]],{n,1,100}]

PARI

a(n) = sum(k=1, n-1, eulerphi(k) >= eulerphi(n)); \\ Michel Marcus, Nov 22 2019

PARI

first(n)=my(u=vectorsmall(n),v=vector(n)); forfactored(f=1,n,u[f[1]]=eulerphi(f)); for(i=1,n, v[i]=sum(j=1,i-1,u[j]>=u[i])); v \\ Charles R Greathouse IV, Dec 11 2019