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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)).
3

%I #13 Mar 04 2018 17:43:58

%S 1,1,2,12,2,90,2,770,2,5460,2,27870,2,86268,2,144,2,120632,2,4584054,

%T 2,1568502,2,147057998,2,1073923452,2,1324614852,2,74007713886,2,

%U 226457341710,2,735893320,2,2038112823132,2,86649033201030,2,4415363800

%N 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)).

%H Diana Mecum, <a href="/A128268/b128268.txt">Table of n, a(n) for n = 0..149</a>

%e 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.

%Y Cf. A128267, A128269.

%K nonn

%O 0,3

%A _Leroy Quet_, Feb 22 2007

%E More terms from _Diana L. Mecum_, Jun 14 2007