A362486 Infinitary nontotient numbers: values not in the range of the infinitary totient function iphi (A091732).

5, 7, 9, 11, 13, 14, 17, 19, 21, 23, 25, 26, 27, 29, 31, 33, 34, 35, 37, 38, 39, 41, 43, 47, 49, 50, 51, 53, 55, 57, 59, 61, 62, 63, 65, 67, 68, 69, 71, 73, 74, 75, 76, 77, 79, 81, 83, 85, 86, 87, 89, 91, 93, 94, 95, 97, 98, 99, 101, 103, 105, 107, 109, 110, 111

Offset: 1

Author

Amiram Eldar, Apr 22 2023

Keywords

• nonn

Comments

Numbers k such that A091732(x) = k has no solution, i.e., A362485(k) = 0.

Most of the odd numbers are in this sequence. Odd numbers that are not here are 1, 3, 15, 45, 255, 765, 3825, 11475, 65535, 196605, 983025, ..., which are the values of iphi at powers of 2.

Links

• Amiram Eldar, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A091732, A362484, A362485.

Similar sequences: A005277, A005278, A347771, A362182.

Programs

Mathematica

Select[Range[120], Length[invIPhi[#]] == 0 &] (* using the function invIPhi from A362484 *)

Formula

A362485(a(n)) = 0.