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