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A263930 Number of quasi-Carmichael numbers less than 10^n. 0

%I

%S 0,2,27,165,734,3109,11568,40820,137850,457191

%N Number of quasi-Carmichael numbers less than 10^n.

%C For quasi-Carmichael numbers see A257750.

%e a(1) = 0 because there are no quasi-Carmichael numbers below 10^1.

%e a(2) = 2 because there are two quasi-Carmichael numbers below 10^2, namely, 35 and 77.

%o (Perl) use ntheory ":all"; my($s,$e)=(0,1); forcomposites { say $e++," $s" if $_ >= 10**$e; $s++ if is_quasi_carmichael($_) } 1e7; # _Dana Jacobsen_, Apr 27 2017

%Y Cf. A055553, A216929, A257750.

%K nonn,more,hard

%O 1,2

%A _Tim Johannes Ohrtmann_, Oct 30 2015

%E a(8)-a(10) from _Dana Jacobsen_, Apr 27 2017

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Last modified April 9 07:30 EDT 2020. Contains 333344 sequences. (Running on oeis4.)