A383017 Numbers k such that A382883(k) = -1.

2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 30, 31, 36, 37, 41, 42, 43, 47, 53, 59, 61, 64, 66, 67, 70, 71, 73, 78, 79, 83, 89, 97, 100, 101, 102, 103, 105, 107, 109, 110, 113, 114, 127, 130, 131, 137, 138, 139, 149, 151, 154, 157, 163, 165, 167, 170, 173, 174, 179

Offset: 1

Author

Peter Luschny, Apr 12 2025

Keywords

• nonn

Comments

See the comments in A382883.

Crossrefs

Cf. A382883, A382943, A383016, A000040, A325264.

Programs

Mathematica

V[n_, e_] := If[e == 1, 1, IntegerExponent[n, e]]; f[n_] := f[n] = -DivisorSum[n, V[n, #] * f[#] &, # < n &]; f[1] = 1; Select[Range[200], f[#] == -1 &] (* Amiram Eldar, Apr 29 2025 *)

SageMath

def A383017List(upto): return [n for n in srange(1, upto) if A382883(n) == -1]

Formula

A382883 = this sequence union A383016 union A382943.

A000040 is a subsequence.