OFFSET
1,1
COMMENTS
The asymptotic density of this sequence is 0 (Erdős et al., 1991).
Since log(log(k))^2 > 1 for k >= 16, the only terms of A033948 (numbers k such that phi(k) = lambda(k)) in this sequence are those below 16.
REFERENCES
József Sándor and Borislav Crstici, Handbook of Number theory II, Kluwer Academic Publishers, 2004, Chapter 3, p. 194.
LINKS
Amiram Eldar, Table of n, a(n) for n = 1..10000
Paul Erdős, Carl Pomerance and Eric Schmutz, Carmichael's lambda function, Acta Arithmetica 58 (1991), pp. 363-385; alternative link.
MATHEMATICA
p[n_] := FactorInteger[n][[-1, 1]]; q[n_] := p[EulerPhi[n]/CarmichaelLambda[n]] / Log[Log[n]]^2 > 1; Select[Range[1000], q]
CROSSREFS
KEYWORD
nonn
AUTHOR
Amiram Eldar, Mar 13 2021
STATUS
approved