A067127 Composite numbers for which phi(n) >= phi(k) for all composite k from 1 to n-1.

4, 6, 8, 9, 14, 15, 16, 20, 21, 25, 33, 35, 39, 45, 49, 65, 77, 85, 91, 95, 111, 115, 119, 121, 143, 155, 161, 169, 187, 203, 209, 217, 221, 247, 253, 287, 289, 319, 323, 341, 361, 391, 403, 407, 427, 437, 451, 473, 481, 493, 517, 527, 529, 583, 589, 611, 629

Offset: 1

Author

Amarnath Murthy, Jan 09 2002

Keywords

• easy
• nonn

Examples

			33 is a member as phi(33)=20 which is >= the maximum phi value for composite numbers less than 33, namely phi(25)=20.
		

Links

• Andrew Howroyd, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A067126, A131195.

Programs

PARI

lista(n)={my(L=List(), m=0); for(k=2, oo, if(!isprime(k), my(t=eulerphi(k)); if(t>=m, listput(L,k); m=t; if(#L>=n, return(Vec(L))))))} \\ Andrew Howroyd, Dec 10 2024