The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A064374 Numbers k such that sigma(k) > phi(k)^2. 2
 2, 4, 6, 10, 12, 18, 30 (list; graph; refs; listen; history; text; internal format)
 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 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: A324059 A055235 A083887 * A000885 A068336 A293821 Adjacent sequences:  A064371 A064372 A064373 * A064375 A064376 A064377 KEYWORD nonn,fini,full AUTHOR Labos Elemer, Sep 27 2001 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified August 8 19:29 EDT 2020. Contains 336298 sequences. (Running on oeis4.)