The OEIS is supported by the many generous donors to the OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A108775 a(n) = floor(sigma(n)/n). 7
 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 1, 2, 1, 2, 1, 1, 1, 2, 1, 1, 1, 2, 1, 2, 1, 1, 1, 1, 1, 2, 1, 1, 1, 2, 1, 2, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 1, 2, 1, 2, 1, 1, 1, 2, 1, 1, 1, 1, 1, 2, 1, 1, 1, 2, 1, 2, 1, 1, 1, 1, 1, 2, 1, 2, 1, 1, 1, 2, 1, 1, 1, 2, 1, 2, 1, 1, 1, 1, 1, 2, 1, 1, 1, 2, 1, 2, 1, 2, 1 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,6 COMMENTS The sequence is unbounded. - Vrabec First occurrence of k: 1,6,120,27720,..., which is A023199. - Robert G. Wilson v, Jun 28 2005 a(n) > 1 if n is perfect or abundant. a(n) = 2 if n is perfect or primitive abundant (see A091191). - Alonso del Arte, Feb 06 2012 REFERENCES W. Sierpinski, Elementary Theory of Numbers, 1987, p. 174 ff. LINKS Reinhard Zumkeller, Table of n, a(n) for n = 1..10000 FORMULA a(n) = floor(A017665(n)/A017666(n)). - Michel Marcus, Sep 18 2015 EXAMPLE a(6) = 2 because sigma(6)/6 = (1 + 2 + 3 + 6)/6 = 2. MATHEMATICA Table[ Floor[ DivisorSigma[1, n]/n], {n, 105}] (* Robert G. Wilson v, Jun 28 2005 *) PROG (Haskell) a108775 n = div (a000203 n) n -- Reinhard Zumkeller, Mar 23 2013 (PARI) a(n) = sigma(n)\n; \\ Michel Marcus, Sep 18 2015 CROSSREFS Cf. A000203, A054024. Cf. A017665, A017666. Sequence in context: A107577 A073700 A226957 * A300826 A373126 A334926 Adjacent sequences: A108772 A108773 A108774 * A108776 A108777 A108778 KEYWORD nonn AUTHOR Franz Vrabec, Jun 27 2005 EXTENSIONS More terms from Robert G. Wilson v, Jun 28 2005 STATUS approved

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

Last modified August 7 10:36 EDT 2024. Contains 375011 sequences. (Running on oeis4.)