A354098 Numbers k such that the cototient of k (= k-phi(k)) is a multiple of 4.

1, 6, 8, 12, 14, 16, 18, 20, 22, 24, 28, 32, 36, 38, 40, 44, 46, 48, 52, 54, 56, 60, 62, 64, 68, 72, 76, 80, 84, 86, 88, 92, 94, 96, 98, 100, 104, 108, 112, 116, 118, 120, 124, 128, 132, 134, 136, 140, 142, 144, 148, 152, 156, 158, 160, 162, 164, 166, 168, 172, 176, 180, 184, 188, 192, 196, 200, 204, 206, 208, 212

Offset

1,2

Comments

Union of {1}, A008586 \ {0, 4} and A196445 \ {2}. - Amiram Eldar, Dec 21 2023

Links

Table of n, a(n) for n=1..71.

Mathematica

Select[Range[200], Divisible[# - EulerPhi[#], 4] &] (* Amiram Eldar, May 17 2022 *)

Prog

(PARI)
A354097(n) = (0==((n-eulerphi(n))%4));
isA354098(n) = A354097(n);

Crossrefs

Cf. A000010, A010873, A051953, A354097 (characteristic function).

Cf. also A292763, A354038.

Cf. A008586, A196445.

Sequence in context: A315856 A265360 A182253 * A026601 A287435 A287419

Adjacent sequences: A354095 A354096 A354097 * A354099 A354100 A354101

Keyword

nonn

Author

Antti Karttunen, May 17 2022

Status

approved