1,3

The integers coprime to a(1)=1 are: 1,2,3,4,5,6,... The 5th of these is 5. The integers coprime to a(2)=1 are: 1,2,3,4,5... The 4th of these is 4. The integers coprime to a(3)=3 are: 1,2,4,5,7,... The 3rd of these is 4. The integers coprime to a(4)=6 are: 1,5,7,11,... The 2nd of these is 5. And the integers coprime to a(5)=10 are: 1,3,7,9,11,... The 1st of these is 1. So a(6) = 5 + 4 + 4 + 5 + 1 = 19.

Cf. A132273, A132275.

Adjacent sequences: A132271 A132272 A132273 this_sequence A132275 A132276 A132277

Sequence in context: A029864 A075111 A080014 this_sequence A091714 A017991 A065614

more,nonn

Leroy Quet (qq-quet(AT)mindspring.com), Aug 16 2007