1,2

The first 7 terms of the sequence are 1,2,4,3,8,5,12. Of these there are 3 terms that are coprime to 8 (those terms being 1, 3, and 5). So a(8) is the 3rd positive integer missing from the first 7 terms of the sequence (i.e. is the 3rd integer of the sequence 6, 7, 9, 10, 11, 13,..). So a(8) = 9.

Cf. A118784.

Sequence in context: A131395 A109812 A137622 this_sequence A120242 A054427 A048672

Adjacent sequences: A118780 A118781 A118782 this_sequence A118784 A118785 A118786

more,nonn

Leroy Quet (qq-quet(AT)mindspring.com), Apr 29 2006