login
A362486
Infinitary nontotient numbers: values not in the range of the infinitary totient function iphi (A091732).
4
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
1,1
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
FORMULA
A362485(a(n)) = 0.
MATHEMATICA
Select[Range[120], Length[invIPhi[#]] == 0 &] (* using the function invIPhi from A362484 *)
CROSSREFS
Similar sequences: A005277, A005278, A347771, A362182.
Sequence in context: A325797 A128163 A177088 * A168146 A343064 A106505
KEYWORD
nonn
AUTHOR
Amiram Eldar, Apr 22 2023
STATUS
approved