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A141711 Carmichael numbers with more than 3 prime factors. 8
41041, 62745, 63973, 75361, 101101, 126217, 172081, 188461, 278545, 340561, 449065, 552721, 656601, 658801, 670033, 748657, 825265, 838201, 852841, 997633, 1033669, 1050985, 1082809, 1569457, 1773289, 2100901, 2113921, 2433601 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Sequence A087788 gives Carmichael numbers with exactly 3 prime factors; since they cannot have fewer (cf. references in A002997), this sequence is the complement of A087788 in A002997.

The terms preceding a(17) = 825265 = A006931(5) have exactly 4 prime factors. See A112428 - A112432 for Carmichael numbers with exactly 5, ..., 9 prime factors. - M. F. Hasler, Apr 14 2015

LINKS

Amiram Eldar, Table of n, a(n) for n = 1..10000

FORMULA

A141711 = A002997 \ A087788 = A074379 U A112428 U A112429 U A112430 U A112431 U A112432 U ...

EXAMPLE

a(17)=825265 is the least Carmichael number having more than 4 divisors, thus the sequence differs from A074379 only from that term on.

MATHEMATICA

ok[n_] :=  Divisible[n - 1, CarmichaelLambda[n]] && Length[FactorInteger[n]] > 3; Select[ Range[3*10^6], ok] (* Jean-Fran├žois Alcover, Sep 23 2011 *)

PROG

(PARI) A2997=readvec("b002997.gp"); A002997(n)=A2997[n]; for( n=1, 100, omega( A002997(n) ) > 3 & print1( A002997(n)", "))

CROSSREFS

Cf. A002997, A087788, A074379, A112428 - A112432, A006931.

Sequence in context: A033532 A173361 A047828 * A074379 A237395 A252121

Adjacent sequences:  A141708 A141709 A141710 * A141712 A141713 A141714

KEYWORD

nonn

AUTHOR

M. F. Hasler, Jul 01 2008

STATUS

approved

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Last modified August 1 14:44 EDT 2021. Contains 346393 sequences. (Running on oeis4.)