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, 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

Offset

1,3

Links

Table of n, a(n) for n=1..85.

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