This site is supported by donations to The OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A099042 Number of badly sieved (A066680) divisors of n. 5
 0, 1, 1, 1, 1, 2, 1, 2, 1, 2, 1, 3, 1, 2, 2, 2, 1, 3, 1, 2, 2, 2, 1, 4, 1, 2, 2, 2, 1, 4, 1, 2, 2, 2, 2, 4, 1, 2, 2, 3, 1, 3, 1, 2, 3, 2, 1, 4, 1, 3, 2, 2, 1, 4, 2, 3, 2, 2, 1, 5, 1, 2, 3, 2, 2, 3, 1, 2, 2, 4, 1, 5, 1, 2, 3, 2, 2, 3, 1, 4, 2, 2, 1, 4, 2, 2, 2, 3, 1, 6, 2, 2, 2, 2, 2, 4, 1, 3, 2, 3, 1, 3, 1, 3, 4 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,6 COMMENTS A001221(n) <= a(n) <= A000005(n). LINKS Antti Karttunen, Table of n, a(n) for n = 1..65537 FORMULA a(n) = Sum_{d|n} A099104(d). - Antti Karttunen, Jul 02 2018 EXAMPLE a(24) = #{2,3,8,12} = 4; A099043(24) = 2+3+8+12 = 25; a(25) = #{5} = 1; A099043(25) = 5; a(26) = #{2,13} = 2; A099043(26) = 2+13 = 15. PROG (PARI) A099104(n) = if(1==n, 0, my(m=1); fordiv(n, d, if((d=n), m *= (1-A099104(d)))); (m)); A099042(n) = sumdiv(n, d, A099104(d)); \\ Antti Karttunen, Jul 02 2018 CROSSREFS Cf. A066680, A099104. Sequence in context: A241276 A325759 A292286 * A140774 A056924 A316364 Adjacent sequences:  A099039 A099040 A099041 * A099043 A099044 A099045 KEYWORD nonn AUTHOR Reinhard Zumkeller, Sep 23 2004 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 October 19 16:17 EDT 2019. Contains 328223 sequences. (Running on oeis4.)