A130499 a(1)=1. a(n) = number of earlier terms of the sequence which are coprime to (the sum of positive integers which are <=n and missing from first (n-1) terms of sequence).

1, 1, 2, 3, 3, 3, 5, 6, 6, 6, 10, 5, 7, 13, 14, 6, 9, 17, 18, 5, 7, 13, 13, 7, 13, 13, 8, 27, 24, 25, 30, 19, 30, 15, 29, 17, 36, 22, 19, 15, 40, 41, 16, 39, 38, 24, 28, 28, 48, 39, 29, 30, 50, 34, 30, 30, 55, 31, 25, 25, 30, 61, 44, 29, 27, 37, 38, 36, 65, 28, 63, 38, 45, 28, 54

Offset

1,3

Links

Diana Mecum, Table of n, a(n) for n=1,...,569

Example

The positive integers which are <= 9 and are missing from the first 8 terms of the sequence are 4,7,8,9. The sum of these integers is 28, so a(9) is the number of earlier terms which are coprime to 28. Therefore a(9) = 6.

Crossrefs

Cf. A130498.

Sequence in context: A141418 A287771 A335107 * A020910 A029065 A263253

Adjacent sequences: A130496 A130497 A130498 * A130500 A130501 A130502

Keyword

nonn

Author

Leroy Quet, May 31 2007

Extensions

Added terms a(12) - a(569) Diana L. Mecum, Jan 01 2009

Status

approved