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A064374
Numbers k such that sigma(k) > phi(k)^2.
2
2, 4, 6, 10, 12, 18, 30
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OFFSET
1,1
COMMENTS
Also numbers k such that sigma(k) > tau(k)*phi(k). -
Benoit Cloitre
, Aug 06 2002
There are no further terms. -
Benoit Cloitre
, Aug 06 2002
LINKS
Table of n, a(n) for n=1..7.
FORMULA
Solutions to
A000203
(k) >
A000010
(k)^2.
EXAMPLE
k = {2, 4, 6, 10, 12, 18, 30};
sigma(k) = {3, 7, 12, 18, 28, 39, 72};
phi(k) = {1, 2, 2, 4, 4, 6, 8};
phi(k)^2 = {1, 4, 4, 16, 16, 36, 64};
sigma(k) - phi(k)^2 = {2, 3, 8, 2, 12, 3, 8}.
No more solutions below 10000000.
CROSSREFS
Cf.
A000010
,
A000203
,
A055234
.
Sequence in context:
A055235
A083887
A339736
*
A000885
A372638
A068336
Adjacent sequences:
A064371
A064372
A064373
*
A064375
A064376
A064377
KEYWORD
nonn
,
fini
,
full
AUTHOR
Labos Elemer
, Sep 27 2001
STATUS
approved
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Last modified June 5 16:08 EDT 2024. Contains 373107 sequences. (Running on oeis4.)