A123302 a(0) = 1. a(n) = the n-th integer from among those positive integers coprime to a(n-1).

1, 1, 2, 5, 4, 9, 8, 13, 8, 17, 10, 27, 17, 13, 15, 28, 37, 17, 19, 20, 49, 24, 65, 31, 24, 73, 26, 57, 44, 63, 52, 67, 32, 65, 46, 73, 36, 109, 38, 81, 59, 41, 43, 44, 95, 59, 46, 97, 48, 145, 64, 101, 52, 113, 54, 163, 56, 131, 58, 121, 65, 82, 127, 63, 110, 177, 100, 167, 68

Offset

0,3

Links

Table of n, a(n) for n=0..68.

Example

The positive integers coprime to a(6)=8 are 1,3,5,7,9,11,13,15,17,19... The seventh of these is 13, so a(7) = 13.

Mathematica

f[l_List] := Block[{k = 0, c = Length[l]}, While[c > 0, k++; While[ GCD[k, l[[ -1]]] > 1, k++ ]; c--; ]; Append[l, k]]; Nest[f, {1}, 70] (* Ray Chandler, Nov 11 2006 *)

Crossrefs

Sequence in context: A283419 A114752 A204923 * A227368 A339597 A368736

Adjacent sequences: A123299 A123300 A123301 * A123303 A123304 A123305

Keyword

nonn

Author

Leroy Quet, Nov 08 2006

Extensions

Extended by Ray Chandler, Nov 11 2006

Status

approved