A128268 a(0)=1; a(n) = lcm((number of earlier terms which are coprime to n), (sum of the earlier terms which are coprime to n)).

1, 1, 2, 12, 2, 90, 2, 770, 2, 5460, 2, 27870, 2, 86268, 2, 144, 2, 120632, 2, 4584054, 2, 1568502, 2, 147057998, 2, 1073923452, 2, 1324614852, 2, 74007713886, 2, 226457341710, 2, 735893320, 2, 2038112823132, 2, 86649033201030, 2, 4415363800

Offset

0,3

Links

Diana Mecum, Table of n, a(n) for n = 0..149

Example

Every term among {a(0),a(1),...a(6)} is coprime to 7. There are 7 such terms. And the sum of these terms is 110. So a(8) = lcm(7,110) = 770.

Crossrefs

Cf. A128267, A128269.

Sequence in context: A010239 A320975 A222804 * A185633 A246737 A012626

Adjacent sequences: A128265 A128266 A128267 * A128269 A128270 A128271

Keyword

nonn

Author

Leroy Quet, Feb 22 2007

Extensions

More terms from Diana L. Mecum, Jun 14 2007

Status

approved