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A362664 Numbers k with exactly two solutions x to the equation iphi(x) = k, where iphi is the infinitary totient function A091732. 2
1, 2, 3, 4, 10, 15, 20, 22, 28, 42, 44, 45, 46, 52, 54, 56, 58, 70, 78, 82, 92, 100, 102, 104, 106, 116, 130, 136, 140, 148, 162, 164, 166, 172, 174, 178, 184, 190, 196, 200, 204, 208, 212, 220, 222, 226, 228, 234, 238, 246, 250, 255, 260, 262, 268, 272, 282, 292, 296 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,2
COMMENTS
Numbers k such that A362485(k) = 2.
There are no numbers k with a single solution to iphi(x) = k, because if iphi(x) = k, and A007814(x) is even, then 2*x is also a solution, i.e., iphi(2*x) = k.
LINKS
MATHEMATICA
Select[Range[300], Length[invIPhi[#]] == 2 &] (* using the function invIPhi from A362484 *)
CROSSREFS
Similar sequences: A361969, A362185.
Sequence in context: A115195 A095384 A177084 * A115899 A183527 A085934
KEYWORD
nonn
AUTHOR
Amiram Eldar, Apr 29 2023
STATUS
approved

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Last modified May 23 01:37 EDT 2024. Contains 372758 sequences. (Running on oeis4.)