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A232167
Number of composite integers k less than 10^n such that lambda(k) divides 2k-2, where lambda is the Carmichael lambda function (A002322).
0
3, 9, 16, 31, 68, 149, 314, 724, 1670, 4063
OFFSET
1,1
COMMENTS
Conjecture: A055553(n)/a(n) has a limit strictly smaller than 1 as n tends to infinity.
MATHEMATICA
For[k = 4; cnt = 0, True, k++, If[CompositeQ[k] && Divisible[2k-2, CarmichaelLambda[k]], cnt++]; If[IntegerQ[n = Log[10, k+1]], Print[n, " ", cnt]]]; (* Jean-François Alcover, Feb 16 2019 *)
CROSSREFS
Sequence in context: A212870 A306447 A257034 * A058538 A197531 A117108
KEYWORD
nonn,more
AUTHOR
EXTENSIONS
a(8)-a(10) from Giovanni Resta, Mar 03 2014
STATUS
approved