A362182 Unitary noncototient numbers: numbers k such that A323410(x) = k has no solution.

2, 3, 5, 330, 1206, 1210, 1656, 1718, 1806, 1866, 1926, 2376, 2982, 3162, 3186, 3342, 4012, 4062, 4194, 4326, 4502, 4662, 4810, 5322, 5466, 6172, 6402, 6462, 6534, 6546, 6672, 6756, 7266, 7430, 7866, 8030, 8140, 8286, 8386, 8562, 8586, 8860, 9114, 9370, 9516, 9906

Offset: 1

Author

Amiram Eldar, Apr 10 2023

Keywords

• nonn

Comments

Numbers k such that A362181(k) = 0.

Are 3 and 5 the only odd terms? There are no other odd terms below 10^5.

Links

• Amiram Eldar, Table of n, a(n) for n = 1..534 (terms below 10^5)

Crossrefs

Cf. A323410, A362181.

The unitary version of A005278.

Similar sequences: A007617, A347771.

Programs

Mathematica

ucototient[n_] := n - Times @@ (Power @@@ FactorInteger[n] - 1); ucototient[1] = 0; With[{max = 2000}, Complement[Range[max], Table[ucototient[n], {n, 1, max^2}]]]