A126801 a(n) = smallest integer which is coprime to n and is > A057237(n).

2, 3, 4, 3, 6, 5, 8, 3, 4, 3, 12, 5, 14, 3, 4, 3, 18, 5, 20, 3, 4, 3, 24, 5, 6, 3, 4, 3, 30, 7, 32, 3, 4, 3, 6, 5, 38, 3, 4, 3, 42, 5, 44, 3, 4, 3, 48, 5, 8, 3, 4, 3, 54, 5, 6, 3, 4, 3, 60, 7, 62, 3, 4, 3, 6, 5, 68, 3, 4, 3, 72, 5, 74, 3, 4, 3, 8, 5, 80, 3

Offset

1,1

Comments

a(n) is also the smallest positive integer m, m > 1, which is coprime to n where (m-1) is not coprime to n.

Links

Table of n, a(n) for n=1..80.

Example

The integers which are coprime to 9 are 1,2,4,5,7,8,10,11,13,14,... Now 1 and 2, but not 3, are coprime to 9, so A057237(9) = 2. The smallest integer > 2 and coprime to 9 is 4. So a(9) = 4.

Maple

A020639 := proc(n) if n = 1 then 1 ; else min(op(numtheory[divisors](n) minus {1})) ; fi ; end: A057237 := proc(n) if n = 1 then 1 ; else A020639(n)-1 ; fi: end: A126801 := proc(n) local a; for a from A057237(n)+1 do if gcd(n, a) = 1 then RETURN(a) ; fi ; od: end: seq(A126801(n), n=1..80) ; # R. J. Mathar, Nov 01 2007

Crossrefs

Cf. A057237.

Sequence in context: A229949 A126214 A378535 * A076945 A074792 A321168

Adjacent sequences: A126798 A126799 A126800 * A126802 A126803 A126804

Keyword

nonn

Author

Leroy Quet, Feb 21 2007

Extensions

More terms from R. J. Mathar, Nov 01 2007

Status

approved