|
|
A328272
|
|
Numbers k >= 3 where a record value of log(phi(k))/log(lambda(k)) is reached, where phi is the Euler totient function (A000010) and lambda is the Carmichael lambda function (A002322).
|
|
1
|
|
|
3, 8, 24, 7280, 13104, 21840, 32760, 65520, 2878785, 5117840, 6909084, 8636355, 19740240, 27636336, 46060560, 69090840, 138181680, 1703601900, 2271469200, 3407203800, 6814407600, 20174525280
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
1,1
|
|
COMMENTS
|
Banks et al. proved that the set {log(phi(k))/log(lambda(k)) | k >= 3} is dense in [1, oo). Therefore this sequence is infinite.
|
|
LINKS
|
|
|
EXAMPLE
|
For k < 8, phi(k) = lambda(k), and log(phi(k))/log(lambda(k))} = 1. For k = 8, phi(8) = 4 and lambda(8) = 2, so log(phi(8))/log(lambda(8)) = log(4)/log(2) = 2 is a record value, and hence 8 is in this sequence.
|
|
MATHEMATICA
|
r[n_] := Log[EulerPhi[n]]/Log[CarmichaelLambda[n]]; rm = 0; s = {}; Do[r1 = r[n]; If[r1 > rm, rm = r1; AppendTo[s, n]], {n, 3, 10^5}]; s
|
|
CROSSREFS
|
|
|
KEYWORD
|
nonn,more,hard
|
|
AUTHOR
|
|
|
EXTENSIONS
|
|
|
STATUS
|
approved
|
|
|
|