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A173941 Numbers k such that tau(lambda(k)) = lambda(tau(k)). 1
1, 2, 4, 6, 8, 12, 24, 100, 168, 180, 264, 300, 468, 552, 684, 1100, 1128, 1260, 1416, 1848, 1992, 2340, 2568, 3276, 3300, 3600, 3864, 4008, 4296, 4788, 4920, 5208, 5448, 6072, 6312, 7056, 7224, 7896, 8184, 8328, 8616, 9192, 9912 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,2
COMMENTS
Previous name: tau(lambda(n)) = lambda(tau(n)) for the sequential application of the number of divisors of n and Carmichael lambda function.
Numbers k such that A000005(A002322(k)) = A002322(A000005(k)).
LINKS
MAPLE
with(numtheory): for n from 1 to 10000 do:if tau(lambda(n))=lambda(tau(n))then
printf(`%d, `, n):else fi:od:
MATHEMATICA
Cases[Range[1000], k_ /; DivisorSigma[0, CarmichaelLambda[k]] == CarmichaelLambda[DivisorSigma[0, k]]]
PROG
(PARI) lambda(n) = lcm(znstar(n)[2]); \\ A002322
isok(k) = numdiv(lambda(k)) == lambda(numdiv(k)); \\ Michel Marcus, Jul 17 2019
CROSSREFS
Sequence in context: A340014 A001217 A131885 * A194406 A371164 A087443
KEYWORD
nonn
AUTHOR
Michel Lagneau, Nov 26 2010
EXTENSIONS
Name edited by Michel Marcus, Mar 18 2016
STATUS
approved

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Last modified March 29 05:43 EDT 2024. Contains 371264 sequences. (Running on oeis4.)