A121274 - OEIS

The OEIS is supported by the many generous donors to the OEIS Foundation.

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).

Other ways to Give

A121274

a(n) = n-th integer from among those positive integers which are coprime to (n-th integer from among those positive integers which are coprime to n).

1, 2, 5, 4, 13, 6, 13, 14, 9, 10, 31, 17, 29, 14, 33, 16, 49, 18, 47, 23, 21, 22, 67, 24, 25, 36, 67, 37, 107, 30, 61, 55, 33, 34, 55, 36, 77, 38, 79, 65, 143, 53, 93, 58, 45, 61, 139, 57, 77, 76, 127, 80, 157, 65, 113, 85, 57, 72, 221, 60, 125, 62, 63, 64, 100, 79, 141, 81

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,2

LINKS

Table of n, a(n) for n=1..68.

EXAMPLE

6 is the 5th positive integer which is coprime to 5. (1,2,3,4,6,7,8.... is the sequence of positive integers which are coprime to 5 and 6 is the 5th such integer.) 1,5,7,11,13,17,19,... are the positive integers which are coprime to 6. 13 is the 5th of these integers, so a(5) = 13.

CROSSREFS

Cf. A069213.

Sequence in context: A285292 A346595 A126356 * A256464 A111681 A073122

Adjacent sequences: A121271 A121272 A121273 * A121275 A121276 A121277

KEYWORD

nonn

AUTHOR

Leroy Quet, Aug 23 2006

EXTENSIONS

Extended by Ray Chandler, Aug 29 2006

STATUS

approved