A130603 a(0)=0, a(n) = the n-th positive integer that is coprime to (a(n-1)+1).

0, 1, 3, 5, 11, 13, 13, 15, 15, 17, 29, 41, 41, 43, 29, 53, 47, 49, 43, 41, 67, 43, 47, 67, 49, 61, 53, 79, 69, 83, 103, 67, 67, 69, 99, 87, 79, 91, 79, 97, 93, 83, 145, 87, 95, 133, 93, 95, 143, 145, 101, 161, 155, 173, 167, 191, 167, 197, 191, 175, 131, 199, 153, 159, 159

Offset

0,3

Links

Vincenzo Librandi, Table of n, a(n) for n = 0..1000

Example

a(8) + 1 = 15 + 1 = 16. The positive integers which are coprime to 16 form the sequence: 1,3,5,7,9,11,13,15,17,19,21,23,... The 9th of these is 17. So a(9) = 17.

Mathematica

a = {0}; For[n = 1, n < 60, n++, i = 0; b = 0; While[i < n, b++; If[GCD[a[[ -1]] + 1, b] == 1, i++ ]]; AppendTo[a, b]]; a (* Stefan Steinerberger, Oct 16 2007 *)

Crossrefs

Cf. A123302.

Sequence in context: A115398 A014597 A357369 * A069977 A284795 A329629

Adjacent sequences: A130600 A130601 A130602 * A130604 A130605 A130606

Keyword

nonn

Author

Leroy Quet, Aug 10 2007

Extensions

More terms from Stefan Steinerberger, Oct 16 2007

More terms from Sean A. Irvine, Mar 03 2010

Status

approved