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!)
 A130500 a(1)=1. a(n) = number of earlier terms of the sequence which divide (the number of positive integers which are <=n and missing from first (n-1) terms of sequence). 1
 1, 1, 2, 3, 3, 4, 4, 5, 5, 4, 5, 2, 7, 7, 4, 7, 2, 11, 11, 2, 9, 9, 7, 10, 10, 2, 11, 2, 17, 17, 8, 8, 11, 2, 17, 5, 9, 7, 18, 18, 2, 18, 2, 17, 8, 15, 15, 11, 23, 23, 2, 12, 12, 4, 26, 26, 2, 20, 20, 2, 24, 24, 13, 13, 16, 16, 2, 31, 31, 7, 21, 21, 8, 24, 2, 24, 11, 31, 4, 16, 2, 37, 37, 2, 21 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,3 LINKS EXAMPLE The positive integers which are <= 9 and are missing from the first 8 terms of the sequence are 6,7,8,9. The number of these integers is 4, so a(9) is the number of earlier terms which divide 4. Therefore a(9) = 5. CROSSREFS Cf. A130501. Sequence in context: A256544 A321211 A336515 * A072073 A320757 A061716 Adjacent sequences:  A130497 A130498 A130499 * A130501 A130502 A130503 KEYWORD nonn AUTHOR Leroy Quet, May 31 2007 EXTENSIONS More terms from Sean A. Irvine, May 26 2010 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 May 9 07:36 EDT 2021. Contains 343692 sequences. (Running on oeis4.)