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

Author

Amiram Eldar, Apr 03 2020

Keywords

• nonn

Examples

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

Links

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

Crossrefs

Cf. A001494, A002322.

Programs

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 *)