A056775 Numbers k such that phi(k+12) = phi(k) + 12.

5, 7, 11, 17, 19, 29, 31, 41, 45, 47, 59, 61, 65, 67, 71, 80, 89, 97, 99, 101, 112, 117, 127, 135, 137, 139, 151, 167, 171, 176, 179, 181, 196, 199, 207, 209, 211, 227, 229, 239, 251, 257, 269, 271, 272, 279, 281, 294, 304, 310, 312, 337, 347, 367, 369, 389

Offset: 1

Author

Labos Elemer, Aug 17 2000

Keywords

• nonn

Comments

Prime solutions are in A046133, common with primes in A015917.

Examples

			65 is a term since phi(65) = 48, phi(65+12) = phi(77) = 60 = 48 + 12.
		

Links

• Amiram Eldar, Table of n, a(n) for n = 1..10000 (terms 1..1000 from Harvey P. Dale)

Crossrefs

Cf. A000010, A001838, A015917, A054902, A046133, A046133.

Programs

Mathematica

Select[Range[400],EulerPhi[#]+12==EulerPhi[#+12]&] (* Harvey P. Dale, Jan 21 2013 *)