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A131347 a(1)=1. a(n) = a(n-1) + (sum of the terms, from among terms a(1) through a(n-1), which are coprime to sum{k=1 to n-1} a(k)). 1

%I #6 Apr 09 2014 10:15:18

%S 1,2,5,11,30,79,175,448,1199,2489,6928,18265,40489,110610,291341,

%T 645395,1633957,2615141,7207226,19135622,50845035,106938617,244812167,

%U 652656533,1686364826,3755787245,4816287969,12353991673,29473426455

%N a(1)=1. a(n) = a(n-1) + (sum of the terms, from among terms a(1) through a(n-1), which are coprime to sum{k=1 to n-1} a(k)).

%e The sum of the first 6 terms of the sequence is 128. There are 4 terms from among the first 6 terms of the sequence that are coprime to 128 (a(1)=1, a(3)=5, a(4)=11, a(6)=79). So a(7)= a(6) + 1 + 5 + 11 + 79 = 175.

%Y Cf. A131346.

%K nonn

%O 1,2

%A _Leroy Quet_, Jul 01 2007

%E More terms from _Joshua Zucker_, Jul 18 2007

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Last modified September 16 12:57 EDT 2024. Contains 375976 sequences. (Running on oeis4.)