A353868 - OEIS

A353868

Numbers k such that the Carmichael function A002322(k) divides Dedekind psi A001615(k).

1, 2, 3, 4, 6, 8, 9, 12, 14, 15, 16, 18, 20, 24, 27, 28, 30, 32, 35, 36, 40, 42, 45, 48, 52, 54, 56, 60, 63, 64, 65, 70, 72, 75, 78, 80, 81, 84, 90, 96, 98, 100, 104, 105, 108, 112, 117, 119, 120, 126, 128, 130, 135, 140, 144, 150, 156, 160, 162, 168, 175, 180, 182, 189, 190, 192, 195, 196, 200, 204, 208, 210, 216

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OFFSET

1,2

COMMENTS

If coprime s,t are terms, then so is s*t. Also, if t is a term and prime p|t, then p*t is also a term. Squarefree terms are listed in A353869, primitive terms are listed in A353870, and their intersection forms A353871.

LINKS

Table of n, a(n) for n=1..73.

user142929, A definition related to pseudoprimes and the Dedekind psi function, MathOverflow, 2022.

MATHEMATICA

psi[1] = 1; psi[n_] := n * Times @@ (1 + 1/Transpose[FactorInteger[n]][[1]]); Select[Range[216], Divisible[psi[#], CarmichaelLambda[#]] &] (* Amiram Eldar, May 09 2022 *)

CROSSREFS

Cf. A002322, A001615, A353869, A353870, A353871.

Sequence in context: A018731 A232966 A331728 * A113961 A116621 A036407

Adjacent sequences: A353865 A353866 A353867 * A353869 A353870 A353871

KEYWORD

nonn,mult

AUTHOR

Max Alekseyev, May 08 2022

STATUS

approved