A058817 Even cototient numbers.

0, 2, 4, 6, 8, 12, 14, 16, 18, 20, 22, 24, 28, 30, 32, 36, 38, 40, 42, 44, 46, 48, 54, 56, 60, 62, 64, 66, 68, 70, 72, 74, 76, 78, 80, 82, 84, 88, 90, 92, 94, 96, 98, 102, 104, 106, 108, 110, 112, 114, 118, 120, 124, 126, 128, 132, 136, 138, 140, 142, 144, 148, 150, 152

Offset

1,2

Links

Donovan Johnson, Table of n, a(n) for n = 1..10001

Formula

Even terms of A063742.

Example

88 is here because it is the cototient of 120: 88 = 120-phi(120) = 120-32 = 88.

Mathematica

With[{max = 300}, Union@ Select[Table[n - EulerPhi[n], {n, 1, max^2}], # < max && EvenQ[#] &]] (* Amiram Eldar, Jan 12 2024 *)

Crossrefs

Cf. A000010, A051953, A063742, A005277, A005278, A002202, A058763.

Sequence in context: A172311 A103829 A164530 * A328593 A254748 A217562

Adjacent sequences: A058814 A058815 A058816 * A058818 A058819 A058820

Keyword

nonn

Author

Labos Elemer, Jan 04 2001

Extensions

Offset corrected by Donovan Johnson, Nov 17 2013

a(1) = 0 inserted by Amiram Eldar, Jan 12 2024

Status

approved