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A068421 Numbers n such that sigma(n) = 6*(n - phi(n)). 0
5, 637, 2225 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
COMMENTS
No other term < 3500000. - Emeric Deutsch, Mar 08 2006
a(4) > 10^12. - Giovanni Resta, Nov 03 2012
LINKS
Table of n, a(n) for n=1..3.
MAPLE
with(numtheory): a:=proc(n) if sigma(n)=6*(n-phi(n)) then n else fi end: seq(a(n), n=1..5000); # Emeric Deutsch, Mar 08 2006
CROSSREFS
Cf. A000010, A000203.
Sequence in context: A256070 A203339 A253690 * A142535 A203475 A203701
Adjacent sequences: A068418 A068419 A068420 * A068422 A068423 A068424
KEYWORD
more,nonn,bref
AUTHOR
Benoit Cloitre, Mar 02 2002
STATUS
approved

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Last modified May 13 07:22 EDT 2024. Contains 372498 sequences. (Running on oeis4.)