A333742 Numbers k such that lambda(k) = lambda(k+2), where lambda is the Carmichael lambda function (A002322).

4, 6, 7, 180, 208, 427, 1183, 1330, 1404, 1480, 1584, 1651, 1672, 2013, 2695, 2715, 3256, 3439, 5250, 5668, 5698, 5950, 5955, 7600, 12243, 13392, 13715, 14768, 22263, 22878, 23347, 24804, 26100, 30500, 32940, 43648, 45870, 46205, 52548, 54481, 59148, 59780, 62719

Offset

1,1

Links

Amiram Eldar, Table of n, a(n) for n = 1..5000

Example

4 is a term since lambda(4) = lambda(6) = 2.

Mathematica

Select[Range[10^4], CarmichaelLambda[#] == CarmichaelLambda[# + 2] &]
Position[Partition[CarmichaelLambda[Range[63000]], 3, 1], _?(#[[3]]==#[[1]]&), 1, Heads->False]//Flatten (* Harvey P. Dale, Aug 16 2024 *)

Crossrefs

Cf. A001494, A002322.

Sequence in context: A102133 A192121 A012760 * A107648 A004786 A263357

Adjacent sequences: A333739 A333740 A333741 * A333743 A333744 A333745

Keyword

nonn

Author

Amiram Eldar, Apr 03 2020

Status

approved